Otto Kudrna

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Otto,

What retracts are you using on the Skyraider. I picked up a set from a GS TF corsair (Robart 150?). Are you making your own landing gear fairings?

snyder_man

Snyder Man
I am using the Robart #615 retracts with the larger 1/2" #670 Robostrut cut down to length. I am producing a scale canopy for it right now and am making a plug for a scale cowl. I am also cutting down the wing to 76" to make it more scale in relationship to the fuse. I am also making the dorsal gusset for the tail and redoing the rudder. I will post a picture in each post on how I do everything. Starting with this post.

What you are looking at in this picture is;
1) the extra fire wall lip cut down
2) aluminum engine mount extension mounted to accommodate RCV90.
3) new scale canopy pined on.

Otto Kudrna

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What you are looking at here is;
1) built up dorsal gusset and initial fill in.
2) narrowing down of vertical fin and reattaching removed piece to rudder section after turning up-side-down.
3) adding 1/4" bass strip to trailing edge of rudder to widen even more. The stab on this airplane is too wide and the rudder is about 35% too narrow that is why this is all done. Also the angle of the trailing edge of the rudder is too vertical, that is why I flip the cut off section up-side down. This gives the rudder the required forward sweep.

Otto Kudrna

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What you are looking at here is;

1) RCV90 test fit with 20x12 prop mounted.
2) top air scoop hollowed out and pined on for test fit. The scoop was also angled up a few degrees and scale aerodynamic fillet made underneath. Fuel tank you see in picture is a 24oz Hays tank. This tank is sitting on top of what is left of the engine bearers.

Otto Kudrna

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What you are looking at here is;

1) finished and sanded dorsal gusset. The white is a special ultra light epoxy filler I make and the blue is automotive glazing putty. any tan you may see is balsa sheet filler blocks underneeth.
2) finished rudder section with scale top hinge. There are two more hinges on the rudder. one in the middle at the protrusion point and one at the bottom. they are both Robart large Hingepoints.
The demarcation lines of the added wood on the rudder are obvious in the picture.

bobripley-RCU

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Hello Otto,

How timely! I bought one of their Skyraiders at Toledo last year and put it away until my Hurricane was completed. Most of the things that I thought I would have to work on you are doing know. Thank you for showing the way. I probably won't start on my until early summer (there is an old Vk DR. I next in line that needs to be finished up first). I will be following your progress with great interest.

Rip

Otto Kudrna

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What you are looking at here is;
1) The original full span wing on the left with original tip shape.
2) On the right is the cut down wing (by 2") Reshaped and reattached wing tip.
3) Cut out section for scale flaps. I will be making scale protruding hinges like on the real aircraft.

Otto Kudrna

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What you are looking at here is a close up of the rudder section, to show in more detail the required added wood and change of angle to make this unit more scale. All the glue lines are visible in this picture to show the different pieces of wood added.

Otto Kudrna

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I hope this thread will help you in building your 4Pi Skyraider, when you are ready. I have one more picture for you this morning before I have to log off and do some work. There is a review on this package in this new (April) issue of "Flying Models" performed by Mr. Nick Zeroli Sr. I helped out a little with the engine and received a Honorable mention in the article

In this picture what you are looking at is a close up of the original flap section and the new flap. The piece which was carefully removed off of the wing was than reattached to the existing flap section. This section was left the original span. The lines are visible on the original wing to help in cut out.

snyder_man

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I was worried that the rotate mech. of the 615 would not be strong enough for the weight of this bird. Several folks have had problems with the rotation gear on landings. That's why I am considering the 150's. Any thoughts?

snyder_man

Otto Kudrna

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I looked at the 150s and thought that they were way too large to fit in the wing. If you think that you can fit them and that they are not too heavy, that is up to you Nick Ziroli used the #115 in his review aircraft in "Flying Models" I am using the next larger strut from what he used and am going to replace the wire stub with a thicker wire.

Otto Kudrna

I am adding a picture of the rudder in the "left turn" position to show how the balancing of the surface works. this should allow me to use a normal small servo for this surface.

Otto Kudrna

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Here is a picture of the original cowl in white and the plug for my new scale cowl in gray.

Otto Kudrna

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Here is a better picture of the hollowed out top scoop and the fillet underneath. this places the scoop in a scale position on the airframe.

Otto

gwk

Where can I get information on 4Pi Kits?

thanks

Otto Kudrna

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This is the extent of 4Pi's Kits. "Skyraider" I will send you a private email.

Otto

kroflite54

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hi otto

I just today ran into your post on the 4pi skyraider.I noticed that the changes your making are for scale purposes but i was going to build it as a sport scale or ,i guess one would say ,semi scale.I have never built a scale model before but have always dreamed of having a skyraider.
I saw them in action in Nam .What a sight to see.would the 4pi raider,as is,be close enough for semi scale(sport scale)?also have you or anyone reading this post seen the 4pi raider fly ?How is the construction of this arc?Anything you can tell me will be appreciated.i plan on buying one in toledo in april
I will be following your progress.
Thanks .Ken

Otto Kudrna

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Hi Ken
Pick up the new issue of Flying models (April) Nick Ziroli did a kit review in the issue.
One of the mods I did, which even though was to scale, was to enlarge the rudder area. Charley bower originally flew this big kit with a ST.75 and the rudder was enough. But if you plan on using anything larger than that, you will find that the mod will be priceless in facilitating proper control of the aircraft. We are using the RCV90 on the airplanes and a 20" prop. The large scale rudder will be a real asset.

Otto

kroflite54

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hi otto.

Thanks for your reply.I will pick up the mag next time i go to hobby shop and thanks for heads up on bigger fin and rudder mod.please keep me informed of your progress and of course,a pic of finished model.

thanks again


Ken

Otto Kudrna

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Hello Ken
I will be doing a more detailed building procedure on www.rcscalebuilder.com . With more detailed explanations of exactly what i did and pictures.

Otto

Hinckley Bill

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Otto,

I do not currently "own" a Skyraider only becasue my stable of kits, partially finished projects and ready to fly planes is already crowding me out of my basement workshop...and aggravating the "little woman" to no end! If she would only let me build that extra attached 3 car garage with a workshop on the second floor there'd be no problems (at least all my stuff wouldn't be so exposed).

But I gotta' tell you that the work you're doing on the Skyraider and sharing with the rest of us is making me wish I could get my hands on one...

Thanks for this wonderful body of work and please continue to update us as you are able...

Bill

Taildrager-inactive

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Hi Otto, what is the ws on your Skyraider? I have a Global Skyraider kit to build and will be following your progress on RC Scale builder ( a great new site) with much interest. Hope to see your Skyraider at St. Charles this summer. Thanks

Otto Kudrna

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The kit spans 80". This makes the span 5" too big for the length of the airplane. The kit was intended to be 1/8 scale but than the manufacturer decided they wanted it to be IMAA legal, so they just spread the ribs apart farther and made it 80" instead of 75". I removed the tip blocks and cut 2" from each tip, than reattached the blocks. I also reshaped the blocks for the correct tip shape which removed another3/4" from each wing. Than I removed 10* from the dihedral to bring it to scale. This all brought the wing to 75", and brings the kit back to the 1/8 scale proper. The fuse is about 3/4" too slender but that dose not seam to affect the appearance of the model. On your Global Skyraider you will find that the problem exists in reverse. The kit was made in some scale, and than stretched in length by about 4 or 5 inches.
Couple of my friends and I had the kit and found it almost impossible to put together. I hate to say this but I threw mine in the garbage and so did two of the other guys. They and I found the tail section almost impossible to build as per instructions. This is why I am building this one.

Otto

kroflite54

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hi otto.

i bought the fourpi skyraider this last toledo show.I'm getting equipment i need now so that i can start it next month.Did you ever do the build in rcscalebuilder.com?I can"t seem to locate it.Did you use the nyrod set up in the wing or did you bypass them and cut in servo pockets?
How was the performance with the rcv 90?I'm thinking of putting either a 90 2 stroke or 120 4 stroke in mine,Your opinions on either would be appreciated.Sorry for all the questions but this will be my first attempt at a warbird.I will be doing the mods that you suggested .
Thanks .ken

Hossfly

You must have an early kit or perhaps a very late one. I bought mine at the SWAC show last October. When I measured the wing parts they totaled 76" in span. Since Charlie advertised 80", I contacted Charlie and he checked some kits-in-stock. He confirmed the 76".

What he did about it I don't know. I will build mine this winter and make it 80" for IMAA events. Just add some tips and blocks in the joints. NBT!

So for you guys that may have a kit of that era, and you want either Big Bird (IMAA) or more scale, I suggest you use the tape before the knife.

For those not familiar with 4-Pi, Charlie Bauer is the AMA District VI AMA DVP. Very nice person he is. Check the AMA web or MA magazine for contact #s.

Thanks for the alerts.

edited to correct Charlie's AMA Dist. CB is D-VI vice VII.

kroflite54

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hi hossfly

i bought mine last april and i was asumming mine was an 80 inch.I'll haVE to measure it now.Are you going to make the rudder mods and as otto did?i've been trying to get ahold of otto but haven't had any luck.
Horrace,are you going to use the nyrod set up thats standard on the fourpi raider or will you bypass and cut servos holes in the wing?When i talked with ziroli at toledo in april he said nyrod setup wasn't to good but made them work.Maybe we can post as we build .
Oh what engine will you be using?


thanks .ken

Hossfly

Rudder mods: Don't know yet but probably not.

Nyrods: No way. I will use separate servos in the wings and probably use internal horn linkages to prevent any control horn display. I don't really build for scale however I hate big horns and push-rods hanging out of wanna'be' scale models. Just my little quirk.

Engine: still to be determined. I will check the structure when I start building. I may use either the G-26, G-38, or maybe a ST 2500, or maybe a Saito 150 gold head all of which I have in the workshop.

Oh so many questions and so few answers. Please forgive me.