D4U Judy Measurements

[GregP]

Hiromachi asked me to get some measurements from the Yokosuka D4Y Judy we have. This is what I came up with.

1) 1 Aileron = 1,225.25 sq in or .7905 sq m, so both ailerons would be twice that area. Our D4Y was restored to static condition and it was elected not to build the aileron trim tabs, so I don't know the size of the aileron trim tabs. If we elect to change this restoration to flight status, new ailerons will have to be built or the existing ones modified for tabs.

2) 1 Flap is 2,173.75 sq in or 1.4024 sq m, so both flaps would be twice that area.

3) 1 Elevator is 1,217.13 sq in or .7852 sq m, so both elevators would be twice that area. The area includes the trim tabs, each of which is 180 sq in or 0.1161 sq m, so the total area for both trim tabs would be twice that area.

4) The rudder is 510 sq in or .3290 sq m including the trim tab. The trim tab is 90 sq in or .0581 sq m.

5) The full travel of the control surfaces was requested, but this restoration was to static display and the travel of the surfaces was never checked to any specifications, so is highly unlikely to be anywhere close to a flyable D4Y's specification.

6) The distance between the center of the two main gear tires is 15 feet 5 inches or 4.6990 m.

The areas are probably not exact, but are pretty close. It broke it up into small sections and added them all up. Most of the sections are rectangular, trapezoids or triangles except for the curved areas at the end of the surface, where I used some straight line approximations to get very close.

 

[GregP]

Hi Hiromachi,

Here's the data you asked for.

 

[Hiromachi]

[edit]
Double post, seems I had some problems with net. If someone could remove it, it would be fine.

 

[Hiromachi]

Oh, wow. Thank you very much Greg. |This is wonderful and helps me a lot.
I'm really thankful.

Can I also ask about something else ?
I saw one video with your Judy on youtube but wanted to ask if you ever sat in cockpit, I mean if it feels comfortable and spacious ?
I'm curious because I lately read some Japanese pilots memoirs, and they liked very much B5N or B6N since there was plenty of "room" and became curious what could be a feeling of Judy cockpit ?

 

[GregP]

Well yes, I have sat in it. Ours isn't finished to fly, so the cockpit is very basic. We have enough engine instruments to start and run and taxi, and we installed working disc brakes, but the pilot's seat is not representative of a service aircraft. Still, it is comfortable and pretty neat to sit in.

When I sat in it, I didn't have a camera with me that day, so I have no record of it. As someone who helped on it, I could probably do it again and get the pic, but I don't care much if I have a pic. I know what I did and that's enough for me. It's very interesting to know how close this aircraft came to being scraped. It was in BAD shape and the consensus was to scrap it. Ed Maloney, the founder of the Museum, bought the wreckage from the museum and paid to have it restored to it's present state himself. It was that close. If you'd have seen the wreckage, you might have scrapped it, too! Ed was one of the only people who was interested in the wreckage. It was that way when he acquired some of our very historic aircraft, too.

Nobody wanted the Seversky AT-12 either until 20+ years after it was acquired to prevent it from being scrapped, too! Ditto a couple of other planes. They turned out to be "hsitoric" only when they were restored and very rare survivors. We have at least three if not more of the "only one left," and we are still flying them.

 

[Hiromachi]

Yeah, I understand. Shame that from many planes which eventually get scrapped ... only few survive. It's a living history.

 

[GregP]

Talk about living history, you can still buy a brand new AN-2 in Poland, can't you? From PZL-Mielek? It would be cool to see a new one! The only ones I've seen are old and in bad shape.

At our museum we have a TS-11 Iskra that is flyable. Nobody seens to fly it, but it flew in to the museum.