Japanese Airfoils, Tora Tora Tora!
Over the last week or so i have been revisiting some of the unknown information I have and trying to fill some data gaps. I went over the data for the Beaufighter VI and rebuilt the engine and props to match what I could find now. I’m happier it’s an improvement with the changes and now very close to max speed specs at all alts.
I invited Tora to pop over for a translation session, we went over my data sets and he brought over a few Maru books we could search in for Airfoil data. Japanese airfoil data is one of the hardest things to get a hold of, I have managed to track a number of airfoils and today we filled in another gap, the NN-5 Airfoil. Tora found a nice diagram of some NN series airfoils, with a loose descriptions referring to the NACA 2200 series. Tora pointed out that at the time of these being designed, the Japanese did not like to refer to anything in it’s American name. ie. NACA 2200 series was American so the Japanese used their own naming convention instead, NN-X.
The NN series (Nakijima Airfoil) had a number of clues which we found in the text associated with the diagrams. The listed the NN-5 2.5 16 and the NN-5 1.4 8 were seeming based on a 2200 series airfoil, the numbers listed seemed to indicate camber and chord data. Reference to thickness at 30% also pointed to 2200 series airfoils being the base and i did some quick plotting in Profili to see how they looked. Lucky for me I had found the NN-2 data plots already and could referance the plots against the 2200 series with chord and camber changes. BINGO 
The plots agreed with the naming convention we had discovered for the NN-5, it was a 2200 series foils with 2.5 camber, 16% chord thickness and 30% chord position. OK, so now we have another wing airfoil gap filled, the B5N now has a wing I’m happy is very close to as it should be.
We have resolved the A6M wing, the G4M wing, the Ki-44 wing and now the B5N wing, a few more exist yet but I am hopeful I can eventually get this information. I continue to scour the net for data and books, the gaps are slowly getting filled and every week I learn something new and refine a bit more my skill and data levels with all different manner of aircraft.
TW is about the journey for me.
Hi Peril, One of our members on the J-aicraft website gave me this thread and I am blown away. I have been searching the web and buying up publications trying to find information on the NN-12 aerofoil as used on the Ki-43. So far I’m not having much luck. I’m booked in to visit the Australian War Memorial in December, so I can take actual measurements from their Ki-43 wing. I am also trying to track down information and tech drawings done by the Texas Airplane Factory when they built four Ki-43 replicas, but this seems to be tightly held interlectural property. Are you interested in the NN-12? Have you had any success finding it?
Which of these airfoils was used for the A6M?
If you still need A6M airfoils, I can help.
Hi there.. i am currently designing a “OSCAR” in 1/5 scale. I have purchased a airfoil program called profilli. i ran across this site while searching for any information on NN-12 airfoil that was used onthe oscar.. I found it interesting that you are refering to the NACA series airfoils. Would by chance the 2200 series apply to the Oscar??? all i have left to do is the wing and i would like to genrate the airfoil using profilli…. would you happen to know hte corresponding NACA number? thank you for your help in this.
regards,
Lester Palifka
nice nice
I am interested im fins ( dorsal ) seen as hydrofoils.
Which profile can best master the characteristcs of water
Sorry, I have no idea, my interest is in aerofoils used on WW2 aircraft.