Warbirdkits.com Nakajima Ki-84-i Hayabusa "Oscar" - RC Groups
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Mar 07, 2006, 11:53 AM
Big gov never Works
St. Martin's Avatar
Discussion

Warbirdkits.com Nakajima Ki-84-i Hayabusa "Oscar"


Greeting's:

Here another "obscure" design from Tom Jacoby.

Scale: 1/12
WS: 35.6"
W Area: 212 sq"
LOA: 27.75"
Power: SP-400 or brushless equivalent.
Battery: 7-8 1100 NiMh or 2-3s Lipo(dependent upon mtr selection, finished wt)

This design is a little larger than most current sized SP-400 types. If the design is one that can be built light, esp. aft of the CG, then the increase in size is a good thing. The cross-section of the rear fuselage is very small. This helps greatly in the lightness way of thinking.

The airframe planeform is not unlike an old style pattern ship. For this reason, I feel that the plane will fly the same. Should be very smooth.

The kit is basically a short kit. Wing sheeting, fuse shting, and a couple of 1/8"sq and a length of 3/8x3/4" LE, is needed. I bought 4-1/16"x 4" shts. The rest I had in my scrap box. My LE was made from assorted lengths of 1/4" and 1/8" sht strips.

The fuselage construction is done on the horizontal "half-shell" method. This is exactly the way He designed the IAR-80. This had a long, small cross-section aft fuse, also. A plus I like in this design, is the all wood cowling. I prefer this over plastic. It's more durable, and reapairs better, in my opinion.

I am undecided as to the poer system I will use. I have a 16/15/5 Mega should I want the speed. Of maybe a cheap outrunner that can swing a 9" prop slower.

I will most likely glass only the fuselage. Sikspan the rest. This has proven to be a good choice for balance of strength where needed and light wt in stronger areas. The fuselage always seeming to take the brunt of all sudden stops.

I started with he fuselage first:

One area I had problems with was the fuselage sheeting. I was able to get the top left side, OK. The right top side, I could not work around the compound curve of the fuselage. So, I opted to do the same as the IAR and plank the fuse w/ 1/16x 3/8" planks. This went fast. I'm sure if I had a better sheet wood, as the left side, I could have sheeted it. As I was this far, I did the whole fuselage, planked. The completed fuselage is very light and stiff. Besure all bulkheads are perpendicular to the crutch! ESP. F-1.
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Mar 07, 2006, 12:26 PM
Big gov never Works
St. Martin's Avatar

"everything fly's better, witha wing"...anonymous..


Yep wing is next. I guess I forgot to say, that I taped the wing skins together, before startting the fuselage. The directions are quite accurate on this step.
The bottom skins are embossed with the spar, rib and aileron locations. The plans are not needed. I fould the location of the ribs and spar lines "spot-on". I did find the aileron spar a little to low in ht. I added 1/8sq scrap to billd up to rib level. I also elected to use a false leading edge. This so that the top sheeting has a level attachment vs the top sheeting butting up against the LE. Don't forget to cut the top skin 1/4" larger in chord than the bottom. Nice time for a reminder..

Tom's manuel discribes the use of wash-out shims. These were not found on the cut sheets. I save all shims, and the ones from the Hornet proved perfect.

Steve
Mar 07, 2006, 07:37 PM
Registered User
Huckebein's Avatar
I can't wait for this one to be available!! I love Japanese warbirds!
Mar 07, 2006, 08:49 PM
EB-66C Team Member
J Morgan's Avatar
Just another great build.

J
Mar 07, 2006, 10:12 PM
Manzano Laser Works
TomJacoby's Avatar
Quote:
Originally Posted by St. Martin
The kit is basically a short kit. Wing sheeting, fuse shting, and a couple of 1/8"sq and a length of 3/8x3/4" LE, is needed. I bought 4-1/16"x 4" shts. The rest I had in my scrap box. My LE was made from assorted lengths of 1/4" and 1/8" sht strips.
Steve, you got a prototype kit. The leading edge sticks will be included in the production kit. Oh, and the builder only needs to furnish the top skin for the wing, as the bottom skins are laser cut and etched. But it will be produced as a short kit.

Quote:
One area I had problems with was the fuselage sheeting. I was able to get the top left side, OK. The right top side, I could not work around the compound curve of the fuselage. So, I opted to do the same as the IAR and plank the fuse w/ 1/16x 3/8" planks.
Planking the fuselage is not necessary. The only break in the straight lines of the fuselage is at the rear of the cockpit. So, we sheet the rear of the fuselage from the rear of the cockpit back with two pieces. Sheet the front with two pieces. I will make this clear in the manual.

Tom
Mar 07, 2006, 10:37 PM
Manzano Laser Works
TomJacoby's Avatar
Quote:
Originally Posted by St. Martin
I did find the aileron spar a little to low in ht. I added 1/8sq scrap to billd up to rib level.
Hmmmm, it was fine on my model. Guess I need to check the cut file...

Quote:
I also elected to use a false leading edge. This so that the top sheeting has a level attachment vs the top sheeting butting up against the LE.
Good idea. I will see about making that change to the kit.

Quote:
Tom's manuel discribes the use of wash-out shims. These were not found on the cut sheets. I save all shims, and the ones from the Hornet proved perfect.
Oops I will add them to the cut file.

-t
Mar 07, 2006, 10:48 PM
Manzano Laser Works
TomJacoby's Avatar
Here's my prototype, before adding the canopy and spinner.

Apparently the WWII Japanese army had some of the world's worst green paint. The stuff weathered, flaked and faded from the moment it was applied! Worse yet, it was generally applied in the field and subject to poor application methods.

To achieve the weathered finish, I started with a spray coat of aluminum color. Once that was dry, I sprayed on a coat of Tamiya dark green, varying the distance from the spray nozzle to the model to simulate field paint application.

Then I attacked the green paint with wads of masking tape, pulling off irregular splotches of the green. Up close, it does fairly represent a chipped, weathered and faded IJAAF green finish.

The white "combat" stripe and yellow leading edge are hand painted to achieve a war-weary look.

The meatball and arrow decals you see here are included in the kit.

Tom
Last edited by TomJacoby; Mar 07, 2006 at 11:02 PM.
Mar 07, 2006, 10:55 PM
Manzano Laser Works
TomJacoby's Avatar
Quote:
Originally Posted by Huckebein
I can't wait for this one to be available!! I love Japanese warbirds!
Thanks! I should have the first production run ready in about two weeks - as long as Steve doesn't find any major problems with the model.

Tom
www.warbirdkits.com
Mar 08, 2006, 05:05 AM
Big gov never Works
St. Martin's Avatar
That makes better sense on the sheeting, Tom. I don't foresee any other problems, Tom. I have basically ran out of parts. I ran out of glass cloth, so a trip to the LHS is neccessary till Ann Booth gets her supply in. THen this one is complete. I'm kind of liking the color scheme on your manual cover.

Steve
Mar 08, 2006, 07:52 AM
Proud of my Westie
Westwhite's Avatar
Really looks good Steve! Hope the snow is finally beginning to abate. Can't wait to see your final dressing on the Hayabusa. Hopefully it will prove as nimble a flyer as its full size counterpart.

cheers,
Monty
Mar 08, 2006, 08:17 AM
Registered User
MikeL72's Avatar
Good to see more of your fine work on Tom's great warbirds. Getting closer to bass days but looks like you'll have this one ready before then.
Mike
Mar 08, 2006, 09:08 AM
Big gov never Works
St. Martin's Avatar
Hi Monty, Hi Mike! I have to wait till the glass arrives brfore I can finish it. But I started this on sunday eve. Very fast build. We have had some nice days recently. But the wind is still gusty. Bass fishing usually arrives before flying weather. As soon as this thin ice sheet leaves, I'll be back spinner-baiting..

Steve
Mar 08, 2006, 11:19 AM
Manzano Laser Works
TomJacoby's Avatar
Steve,

I have decals available for a Royal Thai Air Force version if you want. Now these are catchy paint schemes (courtesy of Wings Palette http://wp.scn.ru/en/ww15/f )

Tom
Mar 08, 2006, 03:20 PM
Big gov never Works
St. Martin's Avatar
I'm still favoring the one depicted on the instruction manual. Mostly, because I have these colors on hand. Otherwise I would do the tiger scheme. Very different. I was able to gater enough pieces of .5oz cloth to glass the fuselage. Will require more sanding, but, I cannot wait for the glass to arrive from Ann. Back later:

Steve
Mar 08, 2006, 08:59 PM
Manzano Laser Works
TomJacoby's Avatar
I used Doculam for the flying surfaces on my Oscar. It's tough and takes paint well.

-t


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