Sorry I've been missing, guys.

Geez, tough crowd. Even your friends forget you. I haven't flown RC in two years either, can you beat that?
Chris...

LOL Chris you got it going on man!! Good to hear from you and yes i would say ya been busy . Congratulations on the win and third place Yes i can beat the haven't flown in RC 3 years . Heck only one time last year or the hear before DUH can't remember for sure The plane is looking good !! You should take us for a Gopro ride in that baby when done Eric

wood working is a relaxing passion....lots of cabinet type and one or two boats

never could cobble the disposable $$$ to play home built real airplane

That wing is simply beautiful craftsmanship

You actually fly in that thing...........or is it 1/2 scale R/C something or other...

Seriously, wooden spars etc.? I thought all those little Pitts Specials likes were made of structural aluminum.

Haven't noticed you as much over on rimfirecentral either.

Bob

I guess you are all grown up , when you go from model planes to real airplanes!  Dang, that wing looks superb! Good luck with the rest of thre renovation.

stuntflyr wrote:Geez, tough crowd. Even your friends forget you. I haven't flown RC in two years either, can you beat that?
Chris...

LOL, JUST KIDDING!!!! Great to hear from you buddy, cool looking project!


https://en.wikipedia.org/wiki/Payne_Knight_Twister

Ha! Did you ever fly that Compensator?
Chris...

Thanks Mark, Eric, Fred, Bob, you guys are great.

Top wing details;
Top picture is the wingtip with 3 ply CF cap because the balsa tips were in too bad of shape to really make look good. The sheeting wouldn't make the contour to the tip so between the tip rib and the second one is balsa block. Adhesive is West Systems epoxy and thickening agent is colloidal silica that is kinda like cabosil.
Second pic is tip after final sanding and a a sealing coat of resin/epoxy.
Third pic is me! With the top wing which is, on the Holiday/Sunday Knight Twister is 19.5 feet in span top and 17.5 feet bottom wing but it's really high aspect ration so the total area is only 81 sq ft. My 17.5 foot span Pitts Specials were 96 sq ft area.
These really haul, this one only had a 125 hp Lycoming and was reported in a letter or note to Don Fairbanks as having a top speed on 170mph. Takes a 180 to get that speed on a Pitts S-1.
I'm really looking forward to this but won't finish it for 3 years. I've got to finish Laura's remodel.
Chris...

Yeah Bob,

Just like on houses, models or boats, wood is a super strong and stable material for building. My parent's Beech Staggerwing had all wood wings as well the popular Stearman WWII trainer does too.

It's a very specific cut and just like models we grade it critically. The spruce spars have to have straight grain with no defects like knots and the grain count and orientation must meet certain parameters. The Knight Twister was designed in 1928 using the latest NACA information. Those calculations for necessary materials were all done by hand, so some rounding up was done to make sure the structure was sound. Even still, the airplane is so little that the rear spar which looks so thick on the open bottom wing picture above is 3/4 inch outboard of the center lamination.

The wings are stiff as a board when done and even after sheeting them fully, they are easy to move and picking them up I don't think the top wing weighs 75 lbs.

Chris...

rsv1cox wrote:You actually fly in that thing...........or is it 1/2 scale R/C something or other...

Seriously, wooden spars etc.?  I thought all those little Pitts Specials likes were made of structural aluminum.

Haven't noticed you as much over on rimfirecentral either.

Bob

stuntflyr wrote:Top wing details;
Top picture is the wingtip with 3 ply CF cap because the balsa tips were in too bad of shape to really make look good. The sheeting wouldn't make the contour to the tip so between the tip rib and the second one is balsa block. Adhesive is West Systems epoxy and thickening agent is colloidal silica that is kinda like cabosil.
Second pic is tip after final sanding and a a sealing coat of resin/epoxy.
Third pic is me! With the top wing which is, on the Holiday/Sunday Knight Twister is 19.5 feet in span top and 17.5 feet bottom wing but it's really high aspect ration so the total area is only 81 sq ft. My 17.5 foot span Pitts Specials were 96 sq ft area.
These really haul, this one only had a 125 hp Lycoming and was reported in a letter or note to Don Fairbanks as having a top speed on 170mph. Takes a 180 to get that speed on a Pitts S-1.
I'm really looking forward to this but won't finish it for 3 years. I've got to finish Laura's remodel.
Chris...

]

Ah, Carbon fiber. Makes sense. I am so 1960's.

I had to google Pitts Special construction materials to find out that indeed the wing is made of wood, and the fuselage tube aluminum. Good enough for the French Spad, good enough for stunt flyers.

stuntflyr wrote:Yeah Bob,

Just like on houses, models or boats, wood is a super strong and stable material for building. My parent's Beech Staggerwing had all wood wings as well the popular Stearman WWII trainer does too.

It's a very specific cut and just like models we grade it critically. The spruce spars have to have straight grain with no defects like knots and the grain count and orientation must meet certain parameters. The Knight Twister was designed in 1928 using the latest NACA information. Those calculations for necessary materials were all done by hand, so some rounding up was done to make sure the structure was sound. Even still, the airplane is so little that the rear spar which looks so thick on the open bottom wing picture above is 3/4 inch outboard of the center lamination.

The wings are stiff as a board when done and even after sheeting them fully, they are easy to move and picking them up I don't think the top wing weighs 75 lbs.

Chris...

rsv1cox wrote:You actually fly in that thing...........or is it 1/2 scale R/C something or other...

Seriously, wooden spars etc.?  I thought all those little Pitts Specials likes were made of structural aluminum.

Haven't noticed you as much over on rimfirecentral either.

Bob

Thanks for bringing me up to date.  Would love to see you and it in action.

Bob

Sure will, Bob.

The airplane's fuselage is, like a Pitts Special, built from steel tubing. 4130 alloy is super strong and very light in the sizes and lengths necessary for fuselage longerons, cross tubes, cabanes (they are streamlined tubing of the same alloy), and motor mounts. I'm going to use an aluminum spring gear for the main gear and the round tailwheel spring is aluminum too.
My fuse is in need of much repair and modification for the main gear, tailwheel spring, seat back recline, and I have no engine or motor mount so will build a new one when I  get an engine.

Here are the steel sheet control horns for the ailerons that were missing that my builder made a CAD file from the paper plans, sent to a cutter and they were laser cut, another buddy welded them up.
The aileron hinges are steel sheet but actually in this case square steel tubing cut to shape, the nut plates were custom made from aluminum.
The bottom pic is my friends Knight Twister Imperial Biplane Class air racer fuselage which i hope to get mine to this stage in 12 months or so. typical construction from steel tubing with an aluminum spring gear.
 
Chris...

 


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stuntflyr wrote:
The wings are stiff as a board...............

Well??????

MAn there is a lot that goes into building a well (full size plane ) should bee good and sound when done though. Are you still racing ? with the Pitts .

Thanks,
You're right that a lot goes into them. I was lucky to find one because they are pretty rare. This one was built pretty well, so the repair is reasonably straightforward but there ate always a few things that need rebuilt from new.

Here are a few pics from this week. Bottom wing is now in the put-back-together stage!



No Eric.
When I got married I retired from racing. Had the Pitts until a Formula 1 race pilot bought it in '08 and he's had it ever since.
Chris...

This week the sheeting went on...

A couple more...

Here is my friend Mark Holiday's Knight Twister. It was built in 1951 and has always been airworthy. It's been recovered three times and had three different engine sizes, 90, 125 and 160 horsepower Lycomings.
Chris...

The Knight Twister goes on. This winter '18/'19 saw the woodwork on the tail finished, and the control system was created, also the gear and tailwheel mounts were made and installed. big stuff, it is all back in my hangar in Tucson now. The wings and tail ready to pant, controls nearly ready to cover, the fuselage 90% done, 90% to go!
Chris...

Fantastic Project !!!

Thanks for the update Chris , she is coming right along ! What engine is going in that beauty ?

Perseverance pays.

Thanks for keeping us in the loop.

Bob

Here are some pics of the finished wood surfaces. They are covered with 1.4 oz cloth and West Systems epoxy. They are sanded and then given a second coat, resin all applied with a short nap roller, and then sanded again. These pics are taken when it is shiny, 'cause I like how it looks then!
Afterward a coat of high build primer and they are ready for base coat/clear coat finish.
Chris...