Fictional German High Altitude Interceptor

F-32

ACCESS: Restricted
Joined
30 January 2023
Messages
13
Reaction score
12
I am unsure if this is the right forum to post this, or if SecretProjects is even the right site, but if i understood correcrly this should be fine. If this post needs to be taken down just tell me and i will remove it!

I've been trying to come up with some at least partly believable combat aircraft that could've arisen from a continuation of the second world war. I'm currently trying to design a german high altitude twin engine interceptor. My main goal is to emulate how Focke-Wulf and later Dornier would design such a plane, based on a design specification for a bomber hunting aircraft of the kind and with horsepower/resource limitations taken into mind, so i figured you guys might be able to weigh in with what could and what couldn't work.

to get some specs out of the way:
- i estimate the center of mass to be somewhere near the leading edge of the wings, though i am unsure. The center of lift should be further enough in the rear if this is the case.
- it is powered by two jumo 213 engines, forward one cooled by an annular radiator while the rear one's cooling system is undecided. Both can be throttled separately and a single one can be run at a time for increased endurance. Air intakes are both on the left, though i'm considering removing the rear and adding an underbelly one, like the fw-190C's TK-11 supercharger in order to retain good performance at a higher altitude. I already have the ducting in place, that's why the front engine's exhaust is piped backwards through the annular propeller ring.
- propellers are both constant speed four bladed paddle props with similar blade shapes (rear ones are just made to fit onto the ring shaped base). They are geared separately and not linked in any way, though the rear one does have its rotation reversed via a gearbox on the crankshaft in order to mitigate torque.
- it is armed with two synchronised MG151/20 cannons mounted above the engine as well as a MK103 motorcannon, though it can be replaced with either another MG151 or a specialized anti-air BK 3,7. Wings have hardpoints for additional gun pods if needed and the forward right side of the cockpit has an internal hardpoint for an MK108 in a schrage musik configuration. there is also a centerline mounting point for a drop tank for increased endurance.
- the aircraft can be fitted with a wing mounted FuG-220 intercept radar (only two of four antennas visible due to the ortographic view) or a hull-fitted photoreconassiance camera. The FuG-220 is currently drawn with a FuG-202 included, but i am unsure of whether both are nessecary.

The idea behind the plane's design was to have a high altitude interceptor with enough horsepower to perform well with various ordinance and provisions, though due to germany's inability to break the 2000HP barrier, a twin engine design was chosen, inspired by the Do-335. The tandem engine configuration was used for both aerodnyamics and pre-existing coupled engines weren't utilised due to cooling issues. Though this is admittedly done partly for aesthetic reasons, contra rotation was dropped in favor of this unorthodox design to reduce maintanence costs and the added weight of the extension shafts and gearing. In reality, i assume the annular prop's gearbox would offset any and all mentioned advantages, though it is a fairly rare propeller configuration so i honestly do not know.

My current worries are:
- high altitude performance. While i believe the wing profile and overall fuselage shape to be fine, there's no denying that two engines weigh a decent bit, and that's sure to drag it downwards even if it has a decent top speed. Similarly, a bulky supercharger will help with engine tremendously, but i am unsure if fitting a single one in would really help if the other, less supercharged engine's performance will drop differently with an altitude increase.
- radar. I have no idea how a FuG-220 could be mounted onto a plane like this. Giving up the idea might be the most realistic course of action, but looking at the parts of a lichtenstein model still makes it seem like it could be crammed into a wing with fair ease. Another option would be to fit a berlin radar and it's dish into a wing pod, as america did with its naval fighters, though i don't know if the berlin radar would even be viable on a plane like this.
- airflow. I do not know how this propeller configuration's wash would affect performance. Turbulent airflow from the forward propeller is surely not going to increase the rear one's performance as they are too far apart to harness the contra-rotating effect, but on the other hand, the Do-335 with a relatively similar configuration was very fast despite this.
- Landing gear. There is currently three configurations that seem viable considerimg the aircraft's center of mass is inconveniently near the front of the wings. One is a standard tailwheel configuration where the inwards-closing front wheels are mechanically rotated forward when deployed to move them in front of the CoM, though this is unfortunately quite complex and still likely to cause a nose-down when braking. Another idea is to have a tandem wheel setup with wing mounted "training wheels", though this feels super unrealistic for the era. Lastly, a tricycle landing gear configuration could maybe be used here, though there is very little space for both the rear landing gears to fold in and the forward one too, though the forward gear could possibly be mounted off-center or rotate to be flat when retracted to remedy this.

Now, i've typed very much, i hope you guys found this interesting and if anyone has some holes to poke in the least believable elements, i'm all ears. I will be updating this thread with the blueprint when possible!

20240514_113716.jpg
 
Last edited by a moderator:
3f07b13ad84eb5141c9914c5d0c4eb10.png
Previous design. Very much outdated but it showcases the Hirth TK 11 underbelly supercharger that i'm considering using. All of the other ducting is fairly bonkers in this one as i knew what i was doing even less...
 
My issue with Design is:
The second propellor in fuselage behind first engine
Next fuselage integrity and stability problems, how works transition from second engine to this ring true fuselage ?

Alternative put cockpit higher, give Second engine a drive shaft to front and
Two engines power counter rotating pair of propellors.
 
My issue with Design is:
The second propellor in fuselage behind first engine
Next fuselage integrity and stability problems, how works transition from second engine to this ring true fuselage ?

Alternative put cockpit higher, give Second engine a drive shaft to front and
Two engines power counter rotating pair of propellors.
Technically the two engines could be geared together by driving the rear one though the front one's cranshaft like on the Arsenal VB 10, though i somehow thought the structural integrity would still be fine considering planes like the martin convoy variants and the daimler-benz jaerger were both seriously considered as viable proposals in the past. As for your question about how the engine powers the ring prop, from how i understand, the propeller lies on a large gear with teeth on the inside, and the crankshaft drives that gear from the inside with a smaller cog. This would mean spars can still go through the center of the propeller for structural reasons, and things like fuel ducting and cables could also be guided through.
 

Attachments

  • 1715709172576.png
    1715709172576.png
    946.8 KB · Views: 29
  • 1715709274706.png
    1715709274706.png
    155.2 KB · Views: 29
  • 1715709740018.png
    1715709740018.png
    432 KB · Views: 41
thanks for explanation
this could work on Daimler Benz fighter do light weight tail
but on this Do-280 this structure has to support a heavy Engine also...
 
thanks for explanation
this could work on Daimler Benz fighter do light weight tail
but on this Do-280 this structure has to support a heavy Engine also...
Ah... i haven't thought of that. Thank you for bringing it up. A contra-rotating propeller is still something i wish to avoid for stylstic reasons but to at least remedy the structural issue i will widen the annular prop's base to fit a more roburst internal structure.
 
... A contra-rotating propeller is still something i wish to avoid for stylstic reasons ...

It is your prerogative to reject Michel's contra-prop argument for stylistic reasons. However, one further argument in favour is that removal of your 'ring' propeller would provide space for both nose-gear retraction and moving the cockpit forward.

A few questions:

1 - You mention FuG 220 radar. Wouldn't your fighter require another crewman to operate that set?

Single pilot alternatives would be sets like FuG 217J-2 Neptun, FuG 350 Naxos, etc.

2 - If your design represents a "continuation" of WW2, won't radar technology have progressed?

As we're firmly into what-if territory here, you could postulate that the RW late-war FuG 240 Berlin set has since been miniaturized. That would allow you to mount a smaller antenna for a centimetric radar in a wing pod (akin to the F6F-3N Hellcats).

3 - If this is a Dornier design, why adopt RLM 8-280 which was already assigned and in use by Heinkel?

Your flying surfaces appear to be influenced by those of the Ta 152H. That suggests a possible designation fix - make your concept a Focke Wulf/Tank design and apply one of the unassigned RLM numbers - say, 'Ta 326'.

If, however, it must remain a Dornier product ... maybe the flying surfaces should be more Dornier-esque? I'm attaching an example images. (Apologies, I jumped the gun and turned this version into a contra-prop type before reading post #6. Oh, and your Jumo 213 air intakes should be on the starboard side.) For fun, I've applied another unassigned RLM designation and called this one 'Do 338'.

Food for thought ...
 

Attachments

  • Do-280-whif-becomes-Do-338.jpg
    Do-280-whif-becomes-Do-338.jpg
    26.5 KB · Views: 38
Not sure why these never send the first time, Update on the two-view. Widened the annular prop, Added TK-11, removed radar, added gun pods.
 

Attachments

  • 20240515_013650.jpg
    20240515_013650.jpg
    1.2 MB · Views: 34
It is your prerogative to reject Michel's contra-prop argument for stylistic reasons. However, one further argument in favour is that removal of your 'ring' propeller would provide space for both nose-gear retraction and moving the cockpit forward.

A few questions:
First off, amazingly mixed together edit. It is very compelling as is already!

To answer these questions:
1. I had actually looked into that in the meantime and gotten a suggestion to use the FuG 217, and it looks like it would be viable to mount it based off of how they mounted them onto Fw-190A's. I had no idea the 220 required multiple crew members though, so it's a good thing you mentioned it.

2. As for the berlin radar, i really want the project this is for to fully accept the state germany is in late-war, even if it's resource shortage has been delayed by a year or two. I want a lot of projects like the berlin radar and most axial turbojet models to be pulled back from planned mass production despite making it through development after germany accepts it won't have the means to sustain them with it's failing industry. I haven't mentioned this but i considered switching out the Jumos of the later models for the relatively simpler Db-603's or 605's to hammer the point a bit more. Even the twin engine setup is a result of the Db-609 engine's development being put on hold indefinetely due to resource allocation. While nothing could really win the germans the war, this plane still did it's job well due to how few new systems it used.

3. Finally, the wing shape along with all other Kurt Tank style details were a good observation. Once again, in the project this plane was originally designed by Focke-Wulf, and the reason for its designation and production company not being Fw, or more accurately Ta, is because the RLM handed the project over to Dornier to allow Focke-Wulf to continue it's production of fighters and the development of their ill-fated amerikabomber.

As for the designations, i thought numbers could repeat as long as their company prefix differed? I just tried to google some examples... my whole life has been a lie apparently, and it looks like i'll have to do a LOT of renaming. Honestly, 326 and 318 are really nice numbers, i'll use one of those if you don't mind!

And lastly, the 213's supercharger intake... i have no idea how i mixed up the sides but i'll go fix that real quick! I see that you actually fixed that on your Do-338
 
What are the advantages of such a convoluted layout supposed to be in the first place? "Looks cool" isn't cutting it in the real world, where design requirements rule.
 
Last edited:
1) Dornier already has a big, twin engine bomber destroyer aircraft: the Do335 Pfeil/Arrow. Powered by a pair of DB605s. MK103 motor-cannon, 2x synchronized MG151/20s in the cowling. I'd expect them to take Tank's design and scrap or sabotage it in favor of the Arrow.

That annular prop would suck to try to maintain, and it'd take a whole new constant-speed hub system developed to work it. No, use a pusher prop and now you don't need to make one of those engines counter-rotate. And now the whole plane looks a LOT like the Do335.
 
What are the advantages of such a convoluted layout supposed to be in the first place? "Looks cool" isn't cutting it in the real world, where design requirements rule.
There is a clash between me still wanting to use this visually interesting configuration and it's infeasibility. Since it is not particularly practical it mostly boils down to how i can justify it's use on the plane.

The only thing i could come up with is that the configuration was chosen to avoid the use of long extension shafts and planetary gearboxes for maintanence reasons but this is already a bit of a joke considering the propeller ring would likely be an even bigger pain to maintain...

I counted, this is the 29th redesign sketch i made of the plane and i tried to use more standardized configurations on more than half of them, and none of those looked as good as with the current configuration. I like realism a lot but i am willing to lower it if it improves a plane's looks by enough of a margin.
 
Last edited:
1) Dornier already has a big, twin engine bomber destroyer aircraft: the Do335 Pfeil/Arrow. Powered by a pair of DB605s. MK103 motor-cannon, 2x synchronized MG151/20s in the cowling. I'd expect them to take Tank's design and scrap or sabotage it in favor of the Arrow.

That annular prop would suck to try to maintain, and it'd take a whole new constant-speed hub system developed to work it. No, use a pusher prop and now you don't need to make one of those engines counter-rotate. And now the whole plane looks a LOT like the Do335.
This is a very fair point, a push-pull system would be the technically correct way to go, and that'd practically make it redundant as it's be like a new pfeil. I do have to ask, could the pfeil still fill the same role? It was intended as a heavy fighter (zerstörer) but from what i read not a dedicated high-altitude one, as sources generally show it's service ceiling as fairly average. The intended role for my Do-280 is as a high altitude interceptor with an extended max payload in comparison to contemporaries like the Ta-152 and the Doras and i'm not sure if a thick winged pfeil would be able to fulfill that.
 
This is a very fair point, a push-pull system would be the technically correct way to go, and that'd practically make it redundant as it's be like a new pfeil. I do have to ask, could the pfeil still fill the same role? It was intended as a heavy fighter (zerstörer) but from what i read not a dedicated high-altitude one, as sources generally show it's service ceiling as fairly average. The intended role for my Do-280 is as a high altitude interceptor with an extended max payload in comparison to contemporaries like the Ta-152 and the Doras and i'm not sure if a thick winged pfeil would be able to fulfill that.
I mean, if/when Germany gets to meet B29s at ludicrous altitude, there will be a huge push for high altitude interceptors.

Since they made High Altitude specialized Ta152/Fw190s (Ta152H and FW190D), I'm sure they'd make a High Altitude Pfeil. Maybe Junkers 213Es, maybe DB603s for power. Long thin wings like the difference between a Ta152H and a Ta152C, you'd need to add ~10.4m^2 wing area... (FW190A has 18.3m^2 wing area, while Ta152H has 23.5m^2 wing area, and a Pfeil is twice the weight of a Ta152.)
 
Oh man, i never knew of that 335 variant, it looks super cool! For some reason i thought a longer wingspan would throw off the balance of such a strangely configured plane but honestly it makes sense that it isn't an issue. I heard its engines were actually perfectly spaced from the CoM so that if they were upgraded later the plane would not require any weight rebalancing.

It does seem though that this fictional design would be doomed from the getgo for not only technical but also political reasons, As Scott Kenny mentioned a bit earlier, since an upgrade to the Do-335 would be far wiser at the stages of the war.
 
I do still wish to share the finalized design, even with it's shaky design choices as this discussion has helped me resolve a lot of the issues.

Though not present on thid picture of the drawing, the RLM number has now been changed to 260 as that one's unassigned. A FuG-217 Neptun radar has been added for low visibility/nighttime interception, the front supercharger intake has been moved to the correct side and the wing roots have been turned into radiators as the rear jumo213 previously had no cooling. MW50 tank has also been moved forward as far as possible for balance reasons. Markings have also been added.

lastly, i made a quick sketch of it intercepting a flight of lend-lease peacemakers just to draw it in flight.

I want to thank all of you, especially Apophenia for the help regarding the design. With all the redesigns i did of this one over the years i'm happy with what it has turned into now!

20240516_012637.jpg A.jpg
 
An interesting project but in the real world alternate timeline this would have been the choice of the RLM. https://en.wikipedia.org/wiki/Blohm_&_Voss_BV_155

The 'C' variant would be cheaper and faster to build with less complication and the one engine to build and maintain. Not to mention fuel.
 
An interesting project but in the real world alternate timeline this would have been the choice of the RLM. https://en.wikipedia.org/wiki/Blohm_&_Voss_BV_155

The 'C' variant would be cheaper and faster to build with less complication and the one engine to build and maintain. Not to mention fuel.

Oh, i looked into the different variants of this thing and from what i've gathered the project was a mess from start to finish. I suppose it would still work this far into the war but from the company changes to the multiple complete redesigns, i just assumed it was a project doomed from the getgo...
 
As an exercise for the grey matter its a fine piece, no error. Where would we humans be without flights of whimsy from time to time? Boring each other about what we found at the back of the sofa ?..........
 

Similar threads

Please donate to support the forum.

Back
Top Bottom