J7W1 Shinden

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Sounds like a reasonable estimate: That's around the ballpark that liquid cooled 1945 aircraft designs with similar power levels were hitting, and the pusher configuration means it's a much more "bullet-shaped" aircraft than the typical 1945 radial. There could be some unpleasant "boat tail drag", but I think the contouring of the spinner and taper just before would keep this to a minimum, especially with the cooling system ejecting additional hot, high-pressure air into this region

Of course, I doubt it would be achieving these values in a real-world scenario, but that's more because of the poor state of Japanese fuel and industry by 1945, and the fact that every engineering project tends to have at least one "ambushed by reality" moment: P-51B tests had problems with the merlin's piping and the cooling system piping corroding one another, and the Mustang was arguably one of the least troubled development histories of a WWII aircraft.
 
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I assume that the performance figures in this thread are those the Japanese hoped to attain with the J7W Shinden and not data from actual flight trials?

Because AFAIK the two J7W prototypes that were completed did not do any full MIL power (1730 hp SL) speed tests?

I reverse engineered what flat plate drag area you would need to attain to get a SL speed of 593 km/h with 1730 hp and got a flat plate drag area of around 0.365 sqr m. This is a flat plate drag area that is only about 95% of the Mustang's and, given that they have roughly the same wing area, you can compare Cdo as well, and the Shinden is consequently (on paper at least) an extremely aerodynamic design.

However, note that while the Shinden is often attributed a wing area of about 20.5 sqr m, it looks like to me (based on the drawing in Burindo's book page 33) that this is more in the order of 21.95 sqr m counting the "wing area" inside the fuselage as per modern convention.

But it's of course entirely possible that a pusher like the Shinden will have a very low drag area because of no slipstream effect over the fuselage and the way the cooling air exits, which may help to reduce the wake behind the fuselage, in combination with the negative pressure gradient the pusher will give on the rear part of the fuselage since it's essentially sucking the air off the rear fuselage backwards,

But I'm not entirely convinced the Japanese were not being a bit optimistic here and that the impressive speed numbers are more a product of wishful thinking than anything else. But maybe someone has data on this? As in actual Cdo/flat plate drag data for the Shinden? Or maybe data on other similar pushers like the Curtiss XP-55 Ascender for example?
 
Interesting: Found some other data on canard pushers and it turns out that the J7W Shinden probably did have a very low Cdo.

However, after getting somewhere on what sort of trimmable Clmax the Shinden should have, it looks like the turn performance was far from stellar because my calculations indicate that the J7W Shinden would be out-turned even by a P-47D-30 Thunderbolt!

And that's even taking into account that it was a canard, which I guess will disappoint some Shinden fans. At least given that some people seem to think that just because it's a canard it has to turn well.
 
Well, it was intended as an interceptor first and foremost, and with the idea that the design could be rapidly converted to use a turbojet once a suitably powerful one was available. Turn rate would not be a priority for such a design, since you would primarily use roll or yaw to quickly align your course with that of a bomber while retaining speed and altitude, instead of aggressively pitching into a hard turn.

"Stiff" pitch response could also protect against over-rotation, important both for the existing pusher prop version to prevent damage, and to the potential jet developments to prevent stalling out on takeoff or landing.

...I realize I'm not doing much here except speculate on information other people already collected.
 
Not a turn fighter you say? Well, here is proof! Look at that 8 g turn!


View: https://www.youtube.com/watch?v=9IiSr3zLS1A
On a more serious note: Now War Thunder is not considered a serious flight sim by many, but they do try to get things like speed and climb rate right, but apparently they did not get the memo on the Shinden's turn capabilities it seems.

And I while do agree with your point about it being designed as an interceptor, even in that department it does have its flaws: Because while it certainly does have the speed box checked, by my calculations it does not have a very impressive climb rate either, which would be a big drawback for an interceptor which not only has to catch up to the B-29's going horizontal, but has to get up there quickly in the first place.

But I think the main problem with the popular perception of the Shinden is connected to it's maneuverability, because many really do seem to think that just because it's a canard, it has to turn well.
 
Any game keeping young people interested in aviation is in my book cool.
I did play warthunder but for the tanks. Aviation there is a tad to comical for my taste as tanks will be for that interested group. Still good fun untill you will have to pay to win. Tank snipers that can kill over a map length. Nehh. I do miss il-2 sometimes.
 

Absolutely. While I don't play War Thunder myself, I do not belong to the "purists" in the flight sim community who are disdainful of War Thunder. Sure, it may not have a 100% correct flight models, but then not everyone wants to spend 15 min doing a cold start-up on an F/A-18 in DCS before getting airborne so each to his own.

But I see now on the stats page in War Thunder that even there the Thunderbolt actually does out-turn the Shinden. But that video I posted where it was pulling 8 g for a while and rolled like an Fw-190 did look a bit wonky didn't it? Anyway, in popular culture and movies there is no shortage of clips where it behaves more like a Zero than anything.

In addition, if I had a $ for every time I heard that canards turn well because they have an "up" instead of a "down" force on their stabilizer/elevator assembly and that that makes them so good in turns, then I would be a very rich man indeed.
 
Did you see the YouTube video of a guy who "built" a stealth Cessna 172 for a flight sim?
 
Shinpachi has done a very accurate 3d model of one.Maybe throw it into a proper Wind tunnel program such as Solidworks Flow Simulations.
 
This post and the one below with climb data are copies from ones I made over at the Secret Projects Forum, but I think they could be of interest here as well.

While I don't have a later Thunderbolt modeled in my C++ simulations, it looks like the J7W1 Shinden would have been much faster than the P-47D-30 over the entire altitude band:



The small "kink" in the Shinden's speed versus altitude from about 8 km up to the critical altitude is due to compressibility effects in the model. However, these effects are difficult to estimate and the result seen in the figure is not specific only to the Shinden's model, but for the time being lacking other data a more general estimate of at what speed the compressibility drag rise should begin to make itself felt.

In addition, it looks like the Shinden's ratio of mass to flat plate drag area is significantly higher than on the Thunderbolt meaning that it should also be able to out-dive it, which is really saying something since the Thunderbolt is usually considered to be the "king" of high speed dives.
 
Did some simulation runs on this fascinating aircraft, this time looking at climb rates.

And while the Shinden's climb rate at higher altitudes and ceiling certainly were impressive, it looks like even such a standard aircraft as the P-47 D-30 matched it at higher altitudes, and even outperformed it at lower.

Certainly, it was much faster, at least as far as I have been able to gather both from Japanese estimates, and from the simulations I did in April and which is posted above, but the climb rate does not seem to have been that impressive.

Still, the speed advantage would have allowed it get away from US escorts, but even so it would still have been difficult for the Japanese to successfully intercept B-29's I think:

First of all, they would have to climb up to meet the attacking force, and during this time they would be at climb speed and very vulnerable to US fighter swooping down from an altitude advantage.

And secondly, looking at the climb chart below, US high escorts could have been flying above the bombers as high as at 11,500 m (37,000 to 38,000 ft) and could convert that altitude advantage into speed, and thus even so catch horizontally faster Shinden's attempting to intercept.

And this is not even taking into account that the US by this time had even more capable fighters than the P-47 D-30, and a numerical advantage to boot.

So even if the Japanese had managed to get a Shinden production line running, it's still hard to see that it would have been a game changer?

 
No. The J7W1 only flew 3 flights in total amassing 45 min and flew no faster than about 250 km/h IIRC, and they had tons of issues to solve before they were ready to take it to 750 km/h. The simulations assume that you have a well functioning airplane and where the engine hp can be converted into thrust without limitations, i.e. assumes those problems fixed.
 
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