Could you have designed a better Warbird?

I think the main landing gear will have to be in the wings, so there would need to be room for that. They will also need to be fully retractable so that the drag remains low.

Could probably be arranged like so:

I added updated drawing of the dedicated ground attack A/C and completed armour weight calculations above.
Venganca made a good case for keeping the twin tail of the Ar-240 and a semi retractable tailwheel. I just deleted the tail dive break (I feel it´s to heavy that far aft and technically complicated).
The main wheel design is quite different from the podded gears as envisioned by Vengenza. Altough I see agree with the advantages.
I base my decision on the fact that the center fuselage section is already an armoured box and thus able to deal with the loads of crash landing events. The service doors may be bulged in and related damage may occur but that´s the most serious risk so far.
The track of the standart three point landing gear is based upon the Fw-190A landing gear, altough it will have a slightly wider track (Arado had experience with them. The company was a first hour license contractor of Focke Wulf). With such a gear, the plane will be able to negotiate rougher field conditions. Ground clearence of the propeller tips is 0.50m in starting condition. The wing with 22% thickness is spacy enough to retract the main wheel into the wings. The tail wheel is half retracting (better servicability).
The plane does look more like a Terrier in it´s actual state.

One last word to internal fuel buncerage.
There will be an option to interchange 300 ltr. drop tanks with SC-250 bombs internally. We just need a hydraulic pump to circle the fuel into the "normal" internal tanks. Up to 3x 300 ltr. drop tanks could be carried this way (internally under armour) but more typical would be one 300 ltr. drop tank and two SC-250 or one drop tank and 2x MK-103. The wingtips have stations for one SC-50 / SD-50 / AB-50 or SD-70 each, drop tanks or larger bombs cannot be carried there.

The overall general weights increased to 4.781kg:

-general weights:
airframe: 1878kg (570kg of those weights are armoured structure)
engines and equipment: 930kg
armour: 875 kg (+570kg armoured structures)

additional weights:
fuel: 250kg / 360 ltr
oil: 18kg
crew: 80kg

usable military loads:
normal internal: 750kg
max. internal: 1000kg (overloaded)

external loads: 200kg -allowed only at 500 kg internal loads (=normal), or 750 kg internal weights (overloaded)

normal take off weight: 4.781kg
maximum take off weight: 5.031kg (overloaded)

Great stuff delcyros!

Looks like the landing gear needs to be abit further out, cause at the moment you can't retract it without hitting the fuselage.

Btw, I was wondering, why not add semi elliptical wing tips to increase lift lower induced drag?

Looking forward to seeing a side view

Delcryos and Soren, the wide-track landing gear you propose would certainly give this plane more ground stability. And Burmese Bandit, that was something that concerned me about my somewhat narrow-track podded gear. I proposed them partly because I was doubtful the wings would accomodate landing gear without them being inordinately long - apparently they can. Soren, your comment about drag is correct, of course. The podded gear would create more drag, but I didn't think speed was too much of a concern for this plane (although speed is always nice to have if you can get it). The only concern I have about your gear is how long they are - how well are they going to stand up to rough-field conditions? The FW-190 also had long, wide-track gear, and I suppose they did pretty well operating from rough strips on the Ostfront so that may not be a valid concern. On the subject of the FW-190, I always liked the way the semi-retractable tail wheel operated. No doors, no pneumatic, electric, or hydraulic retraction - it was pulled mechanically straight up into the fin by a pulley arrangment utilizing a wire attached to the main gear. Very simple, rugged, and very reliable - perfect for a tough, ground-attack plane. Your creation's starting to look very interesting, delcryos. I like the new pictures you've added, but I'm with Soren - do you have any sideviews you can show us?

Venganza

The gear mechanism appearently does not interfere with either the airscoops or the fuselage. The relevant detail wa snot visible in the graph above so please compare the attached picture below.

I avoided semi elliptical wingtips for two reasons:
A) building simplicity
B) wingtip stations

The latter was more important for me. Originally I intended the wingtip stations for SD-250 bombs but after doing some maths, this goal appeared to be unreasonable. To much structure weight was necessary and the stability was cast in question, too.
But two 50 or 70 kg bombs may be carried there. A nice addition to the offensive suite.
Possibly, elliptical wingtip fairings are an option in case the wingtip ETC is not used for bomb carriers. But I take this to be some kind of "extra", rather than standart.
Unfortunately, I do not have a complete side picture yet. It takes some time for me to prepare them.

Hi Delcyros,

On that picture they fit, but on the other one they don't, they're too long. I actually measured them with a ruler on the screen

hmmm, something seems to be wrong with my first drawing. Thanks for the pointer.
I reused an older version for frontal graphs and used to work with the cutaway drawing.
Some differences appeared.

Note that the airscoops are in front of the wheel bay and turn back inwards so that they don´t interfere (it is depicted the other way in order to show how far the wheels extend wrt fuselage). At the gear bay, the thickness of the wing is avg. 35cm.

performance projections to follow soon.

Roger, looks good now Delcyros

Btw, the airscoops need to be rounded to match your previous sketch of them. I'd make them follow the curvature of the fuselage, to cut down drag.

That´s the way to do.

Here is a size comparison of some ww2 ground attack A/C. The designation Ar-137 is purely hypothetical.

It makes for a difficult target to hit -the whole frontal area is armoured to some extant.

That is one small aircraft!

That is a small plane! Perhaps you've already covered this delcryos, but what kind of dive-bombing would it be capable of - I mean at what angle? One thing that helped the Shturmovik, quite a large plane as is evident from your frontal views, reduce its vulnerability was a change in tactic where it increased its dive angle towards the target (up to 40%, I believe). In addition to increasing the altitude at which the attack started, the additional speed reduced the time over the target, very useful for any attack plane. With a fairly steep dive angle, and such a small frontal area, your Ar-137 would be almost invisible in a dive. I realize you've discarded the Ar-240 type rear fuselage "petal" dive brakes, and for good reason, but how about split flaps for brakes?

Venganza

It is already enforced to undertake "schräganflüge" / shallow dives up to 30deg. Split flaps would allow near vertical dives only if the flap area get´s increased, which would require about 11.29m minimum span for 25% deep flaps (deeper flaps would be difficult in the choosen airfoil due to alteration of center of lift and weight). I would like to avoid the increase in wing area for reasons already outlined above. Split flaps would allow steeper dive angles in the given configuration, perhaps up to 45 deg -I might be wrong- and should be taken into consideration. Dive bombing isn´t the main purpose.

Here are some versions:

recon / observation:
wingtip stations: none
fuselage weapon bay:
1x Rb20/30, 2 x Rb 50/30, 2 x MG-151/20 with 100 rpg, 1x 300 ltr aux. tank (undroppable).
gross weight:
4.500 kg
endurance:
ca. 3 hours at max. economical cruise
range: max. 1285km at 3000m

short range attack 1:
wingtip stations: 2 x SD-70
fuselage weapon bay:
3x MK 101/30 or MK103/30 with 100rpg.
gross weight:
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

short range attack 2:
wingtip stations: 2 x SC-50 / SD-50
fuselage weapon bay:
2x MK 103/30 with 100rpg; 1 x SC-250 or 1x SD-250 or 1 x AB-250.
gross weight:
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

tank hunter 1:
wingtip stations: 2 x SD-70
fuselage weapon bay:
1x BK 3,7, 37mm with 10 x 6 round clips each; 2 x MG 151/15 with 200 rpg each.
gross weight:
4.750 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

tank hunter 2:
wingtip stations: none
fuselage weapon bay:
1 x BK-5, 50mm with 22 rpg and 2 x MG 151/15 with 100 rpg
gross weight:
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 790 km at 3000m

tank hunter 3 (overloaded):
wingtip stations: none
fuselage weapon bay:
1 x BK-7,5 with 12 rpg
gross weight:
5.231 kg
endurance:
1.8 hours at max. economical cruise
range: max. 700 km at 3000m

short range bomber 1:
wingtip stations: 2 x SC-50/SD-50 to 2 x SD-70
fuselage weapon bay:
8 x SC-50/SD-50 to 8 x SD-70
gross weight:
4.531 kg (with SC/SD-50) to 4731 kg (with SD-70)
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

short range bomber 2:
wingtip stations: none
fuselage weapon bay:
3 x SD-250 or 3x SC-250 or 3x AB-250
gross weight:
4.781 kg
endurance:
1.8 hours at max. economical cruise
range: max. 790 km at 3000m

short range bomber 3 (overloaded):
wingtip stations: none
fuselage weapon bay:
2 x SC-500 or 2 x SD-500 or 2 x PC-500 or 2 x AB-500
gross weight:
5.031 kg
endurance:
1.8 hours at max. economical cruise
range: max. 750 km at 3000m

Since Delcyros has finished his proposal for a new attack plane - and it looks wonderful, and certainly appears to be quite plausible as well - I will now write on my proposal for a minimum change Ju 87 Stuka optimized for tank hunting.

A new forward fuselage for the 87 is to be designed. This will be deeper than the original 87, though not by much more. The deeper forward fuselage is designed so that a BK 37 will be mounted on TOP of the engine, not between the vee of the Engine as in other engine mounted gun designs. In addition a ranging MG 151/20 will be mounted on the cowling, for ranging. The BK will fire though a spinner that now is on top of the engine, not in front as in the original 87.

An armoured airscoop with armoured venetian blinds is directly under the spinner, and is connected to the radiator which is directly under the pilot's and gunner's seats by a tunnel that runs under the V of the inverted engine.

The whole underside of the forward fuselage is built as an armoured shell like the Stormovik, and the rear gunner is protected by armour as well. This will add 1,000 kg to the total weight, again like the Stormovik. The gun and ammunition will add about 200 kg. Since the historical 87 could carry up to a single 1800 kg bomb this is well within its load carrying limit.
50-70 rounds of 37 mm ammo could be carried.

The rear fuselage, tail, wings, landing gear, cockpit, rear guns will be like the original 87.

This tank hunter, with its centerline armament and heavy armour, would in my opinion have been a much more sucessful design than the historical 87 with two wing guns that were difficult to aim.

BB, that's a good point about the centerline armament being better than the wing guns. Not only do you not have to worry about converging fire to get the most firepower, but you also avoid synchronization problems. What sunk the Shturmovik with the two 37mm cannons was having them wing-mounted (hard to avoid with the single-engined arrangement, without major modifications - which were a no-go with the IL-2's production requirements). The Soviets had problems synchronizing the guns to fire at exactly the same time, so that every time they were fired, the plane yawed and the aim was ruined (which was compounded by recoil dissipation problems). I've been thinking about how to have a tank-killing gun on the centerline of an IL-2, with limited success, but it looks like you've been able to do it with the Stuka. (Although, now that I think about it more, the Soviets were able to mount guns as big as a 45mm in the tiny Yak fighters, so why not in an IL-2?) It'll be great to see the initial drawings of your design.

Venganza

The Russians tried 37s and 45s on the Yak.

Result: cracked engines. crashed aircraft.

The Russians tried mounting the excellent NS-37 on the Stormovik (IMHO the best 37 of the entire war)

Results, as said above by Vengenza.

That was why the Russians suddenly demanded 40mm Hurricanes from Britain...to the intense embarrassment of the Brits, who had just discontinued that entire production line! Second hand Hurri Tankbusters were hurriedly rounded up and sent to the Russkies.

Hi, BB,

That Russian usage of Hurricane IID is very interesting to me. Any good info about that (timeline, where it was used, numbers etc)?

Venganza said:

....
(Although, now that I think about it more, the Soviets were able to mount guns as big as a 45mm in the tiny Yak fighters, so why not in an IL-2?) .....
Venganza

Click to expand...

Mikulin engines (AM-35, -38) have had auxiliary stuff (pumps etc.) attached to the rear of the engine, so that was the thing hampering engine cannon mounting. The Mig-1 -3 were the 'users' of the -35, and were notably poor armed.
The Klimov 105 was derived by French HS-12 series, so the engine cannon was possible from day one.

tomo pauk said:

Mikulin engines (AM-35, -38) have had auxiliary stuff (pumps etc.) attached to the rear of the engine, so that was the thing hampering engine cannon mounting. The Mig-1 -3 were the 'users' of the -35, and were notably poor armed.
The Klimov 105 was derived by French HS-12 series, so the engine cannon was possible from day one.

Click to expand...

I see, that explains it. I knew the Hispanos were designed to accommodate an engine cannon, but I'd forgetten the Klimov 105 was developed from them. And no point in putting a Klimov in a Shturmovik, unless you want it as underpowered as an Hs-129. Thank you for the information, tomo pauk! I learn something new every day about Soviet planes.

Venganza