Thank you very much for your time spent on checking my R&D, much appreciated!
If you've not realised it already, IJ players have a thing for R&D plans. Everyone has their own particular take, and everyone else does something slightly wrong or sub-optimal as a result.
Randy B: I thought that its superior armament (GV19) and 2x250kg bombs could be useful
The devil is in the details.
The Randy B carries the Ho-401 cannon, so while it does have the stronger gun value, the Ho-401 has an accuracy rating of 4 (compared with the typical 20-30 range of value for typical aircraft weapons). That means it's pretty unlikely to hit in air to air combat.
The Nick gets one 20mm cannon, 2 MG's and 2x250kg bombs, so you're effectively spending the R&D effort for a slight performance improvement on the Nick and an extra 20mm cannon. Not worth it IMO.
Peggy (T): how the pilots can be trained?
You can train your IJA pilots in NavB the same way as you do for the IJA. You can't train NavT until the Peggy arrives, so that can be a challenge (and the more reason to move this plane forward ASAP).
IMO it's an essential plane for IJ late-war, as the IJN doesn't have the depth to be able to keep training pilots for naval attack missions (be it for carrier squadrons or land squadrons) alone as the war ramps up in intensity. The IJA (and the Peggy T) is needed to be able to share the load between the two organisations.
Generally speaking, you also need the torpedoes. Given Allied damage control, it takes a few 250kg bombs to cause problems. Much less torpedoes are needed.
LiLy: the main reason is its low payload, how do you use this bomber?
Dedicated IJA anti-shipping platform up until the Peggy T arrives. It's a dive bomber, and it's IJA. It's an absolute steal for what it is.
The low payload is a bit of a disadvantage, but the 100kg bombs will do fine on anything that's smaller than a CA. I've had particular success with them as CVE killers, and they do a good job dealing with Fletcher squadrons as the war progresses.
Bombers: Frances is the choice, Betty only until its arrive.
Nell will be produced for all the time, beside long range base attack I want to use it on Naval Search as well.
I'd just cut the Betty out completely for the sake of it, but that's just me.
Grace: uhm, therefore SR2 and no radar is going to be better anyway?
Yes.
SR 2 isn't all that punishing in my experience, especially not for carrier based aircraft. It's only SR3 and (particularly) SR4 where I feel it bite.
The N-6 radar on the Jill doesn't arrive until 10/44, so the Jill is radar-less until that point.
Grace has 50km/h on the Jill. This is absolutely critical late-war, when overcoming the Allied radar advantage is vital to get good returns. Aircraft speed is an important input into getting the advantage.
Grace is dual purpose, in that it is a dive-bomber with torpedo capability. If you're in a position where a base or carrier has no torpedoes, the Grace is able to effectively attack ships. That's a pretty big consideration, especially in carrier engagements - if for whatever reason the Grace's don't take torpedoes, they'll still be able to attack effectively with bombs. With 2x250kg bombs, that's a reasonable payload. The Jill would be forced to level bomb with reduced accuracy, whereas the Grace can do dive bombing with much better accuracy.
It's an amazing option for the IJN for the flexibility it affords. No other airframe in the IJN arsenal can move between land-based and carrier-based operations, as well as torpedo and dive bombing attack profiles with as much flexibility.
Lorna: my thinking was to use it on ASW duty, radar and MAD are not a good combo?
Miserable range, with ASW patrols the range of an aircraft is cut in half. That gives you 3 hexes of ASW search, which is pretty poor.
Japan doesn't get the MAD until 6/44, and the FM-3 radar on the Lorna doesn't arrive until 6/45. By that point you won't be too fussed about ASW efforts.
Best option is to ditch that, and build extra G3M3. The extra range will be better for you, and they'll get the H-6 radar in 6/44 anyhow.
Jake: my bad, I totally forgot the radar activation! I have to check the radar activations on the editor.
See above comments regarding other radar activation dates. Like I said, the devil is in the details, and once understood makes a lot of otherwise attractive airframes seem much less attractive.
Kami: Ki-119 (2x30)
Minor point, but I'd go for the 115 over the 119. The 115 is effectively the same plane, but arrives 6 months earlier and being a level bomber (the 119 is a fighter bomber) more squadrons can use it. Not worth using the 119 in a fighter bomber role, as the Nick can do it all anyways.
I don't think the dedicated kamikaze planes are worth it. In my experience, you're better using older existing models, as they offer more flexibility via their additional range, and (more importantly) you can build deeper pools. Compare, for example, the Helen IIb vs the Ki-115, or the Frances vs the Toka.
For some extra homework, also worth consideration is the:
J7W1 Shinden as the only realistic late-war option for the IJN land-based fighter cadre.
Ki-74 Patsy as a late-war IJA long-range bomber, perfect for counter-raids on B-29 airbases and long-range kamikaze strikes.
Ki-94 as the IJA's response to the Thunderbolt.