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Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 12:28 pm

I flew one contest in November at Tucson, won that. Didn't fly again (I mean didn't fly C/L one time) until the Southwest Regionals. I did okay but really should be a little more active. Took third.
I'm busy with this build right now which was supposed to be a little later but my friend that is my wood wing guy is retiring in March and he is sure to have the wings and fin and stab done by end of March.
Top picture of the Sunday, later renamed Holiday Knight Twister N5788B in the mid to late 80's I bought as a disassembled project in 2016.
Middle picture is bottom wing after it's leading edges and sheeting were removed. The airplane had a high rate of descent landing and damaged the fuselage and we disassembled the wings to inspect and repair them.
Bottom picture is the top wing all repaired and inspected with it's 1/16th preformed birch leading edges and 1/16th mahogany sheeting between the spars and trailing edges too. The Knight Twister is designed as a cantilever winged biplane that requires no flying or landing wires. The tail is also cantilever with no external bracing.
Chris...







Last edited by stuntflyr on Fri Feb 16, 2018 4:32 pm; edited 4 times in total
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Re: Sorry I've been missing, guys.

Post  Mark Boesen on Mon Feb 12, 2018 12:35 pm

....who are you again?
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 12:37 pm

Geez, tough crowd. Even your friends forget you. I haven't flown RC in two years either, can you beat that?
Chris...
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Re: Sorry I've been missing, guys.

Post  getback on Mon Feb 12, 2018 12:54 pm

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 cheers Beer Cheers 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 Airplane The plane is looking good !! You should take us for a Gopro ride in that baby when done sunny Eric
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Re: Sorry I've been missing, guys.

Post  fredvon4 on Mon Feb 12, 2018 1:32 pm

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
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Re: Sorry I've been missing, guys.

Post  rsv1cox on Mon Feb 12, 2018 2:25 pm

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

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
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Re: Sorry I've been missing, guys.

Post  Marleysky on Mon Feb 12, 2018 3:07 pm

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.
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Re: Sorry I've been missing, guys.

Post  Mark Boesen on Mon Feb 12, 2018 4:06 pm

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
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 4:21 pm

Ha! Did you ever fly that Compensator?
Chris...
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 4:36 pm

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...












Last edited by stuntflyr on Mon Feb 12, 2018 5:11 pm; edited 1 time in total
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 5:09 pm

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... Smile

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
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Re: Sorry I've been missing, guys.

Post  rsv1cox on Mon Feb 12, 2018 5:15 pm

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. Smile
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Re: Sorry I've been missing, guys.

Post  rsv1cox on Mon Feb 12, 2018 5:16 pm

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... Smile

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
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Mon Feb 12, 2018 5:54 pm



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...

 


[=https://servimg.com/view/17199515/135][/url]
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Re: Sorry I've been missing, guys.

Post  Oldenginerod on Tue Feb 13, 2018 5:57 am

stuntflyr wrote:
The wings are stiff as a board...............
Well??????
Laughing Laughing Laughing Laughing Laughing Wink
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Re: Sorry I've been missing, guys.

Post  getback on Wed Feb 14, 2018 7:00 am

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 .
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Fri Feb 16, 2018 1:50 pm

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...
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Re: Sorry I've been missing, guys.

Post  stuntflyr on Fri Feb 16, 2018 1:54 pm

This week the sheeting went on...




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Re: Sorry I've been missing, guys.

Post  stuntflyr on Fri Feb 16, 2018 1:56 pm

A couple more...

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Re: Sorry I've been missing, guys.

Post  stuntflyr on Fri Feb 16, 2018 3:26 pm

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...

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