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Modified SIG Twister

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Re: Modified SIG Twister

Post  JPvelo on Sun Apr 06, 2014 8:44 pm

Ron,
I used the LA .46
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Re: Modified SIG Twister

Post  RknRusty on Sun Apr 06, 2014 8:45 pm

Cribbs74 wrote:...This thing feels heavy already. I am not happy about that. I'll weigh it and see.
That's why you've got a .40 on it!

I waited as late in the build as I possibly could to drill the beams on the Yak. It paid off, as I had to add no weight anywhere to balance it.
Looking good.
Rusty

Dang, three posts while I was writing. I need to write faster.

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Re: Modified SIG Twister

Post  Cribbs74 on Sun Apr 06, 2014 9:23 pm

RknRusty wrote:
Cribbs74 wrote:...This thing feels heavy already. I am not happy about that. I'll weigh it and see.
That's why you've got a .40 on it!

I waited as late in the build as I possibly could to drill the beams on the Yak. It paid off, as I had to add no weight anywhere to balance it.
Looking good.
Rusty

Dang, three posts while I was writing. I need to write faster.

Yeah, I know. I was comparing it to my other .40 powered planes and it just seems heavy already. I still have half ribs, shear webs and 3" balsa block tips to do. Not to mention all the rest of the stuff.

I always drill motor mounts last for that reason. Most times I have to slam the engines all the way back as they come out nose heavy.

I think maybe I have just been spoiled with 7oz Fox .35's
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Re: Modified SIG Twister

Post  JPvelo on Sun Apr 06, 2014 9:24 pm

I don't know how the FP compares to LA as far as power but I was really concerned about weight untill I flew it. Definitely not under powered and floats like crazy on landings. I need to take it to the post office to get weighed but I think it's around 52oz.

Jim
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Re: Modified SIG Twister

Post  Cribbs74 on Sun Apr 06, 2014 9:36 pm

JPvelo wrote:I don't know how the FP compares to LA as far as power but I was really concerned about weight untill I flew it. Definitely not under powered and floats like crazy on landings. I need to take it to the post office to get weighed but I think it's around 52oz.

Jim

Thanks Jim, I am sure the LA is more powerful and I can switch engines if needed. I have a full fuse Twister that is HEAVY and it's powered by a K&B .40 so I am thinking this one should be lighter than that.

It flys well, and floaty like you mentioned. I like the Cardinal better though  Very Happy 
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Re: Modified SIG Twister

Post  Cribbs74 on Sat Apr 12, 2014 11:24 pm

Here is the wing. Another hotel masterpiece!

I decided to pass on the half ribs and just sheet the fore section. I need to do a lot of sanding to make it right. This may negate the sheer webs as well.

Ron

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Re: Modified SIG Twister

Post  Ken Cook on Sun Apr 13, 2014 7:03 am

Ron, I would still put the webs in. The D tube takes care of torsional twist, but it doesn't do much in terms of flex which is what the shear webs do. For the little bit of wood and time, I would reconsider. It's a simple thing to do. They only have to go out from the center a few bays and they don't need to go all the way across. Ken
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Re: Modified SIG Twister

Post  Cribbs74 on Sun Apr 13, 2014 8:20 am

Ok Ken. I will install them. Thanks for the tip
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Re: Modified SIG Twister

Post  Cribbs74 on Mon Oct 13, 2014 5:43 pm

I finally have an update on this. Probably should have been painting my reed speed except it was too wet out today.

Since my last update I decided to take apart the wing and remove the warped leading edge piece. It was a pain, but worth it as it's arrow straight now. I resheeting the LE with SIG super light 1/16 sheet and installed the control assy. I was waiting on a 4" bellcrank, but as luck would have it my wrecked Cardinal had one so I dissected it and salvaged the control assy to include the adjustable leadouts.

The LE sheeting, combined with the center sheeting makes for a really stiff wing. The tip is actually a template for the block tips I plan on making. Yes, I know Ken told me not to bother, but I just want to give it a shot as I like the way they look.

I also need to make a larger stab, the one in the picture is just the stock piece that I cut to shape. The new one will be larger and taper to a point up front.

Here are a few pictures.













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Re: Modified SIG Twister

Post  Kim on Mon Oct 13, 2014 6:42 pm

Looks Good !
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Re: Modified SIG Twister

Post  JPvelo on Mon Oct 13, 2014 6:49 pm

Looks good! I had to replace the leading edge stock in mine as well. I think the name "Twister" refers to the leading edge stock. I wish I would have sheeted  my leading edge.   I stretched my horizontal stab to 21" and it flies great.

Jim
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Re: Modified SIG Twister

Post  roddie on Mon Oct 13, 2014 7:00 pm

Wicked! I wish I was as good at making the time to devote to building/finishing a flying model, the way some of you guys do.. "You" in particular Ron. Many members here have jobs that take them away from home for extended and sometimes indeterminate lengths of time.. yet they're driven to finish and fly their models.

I like this model Ron.. it looks all business.. Popcorn

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Re: Modified SIG Twister

Post  Cribbs74 on Mon Oct 13, 2014 7:59 pm

Thanks Roddie,

Being away from home half the year has it's challenges. Having the tools and supplies on hand make things go quicker, along with space to work. Projects may sit for a couple months, but I can do a months work in a day if I put my mind to it.

I have the ability to hyper-focus which allows me to really concentrate on things I enjoy. I am easily distracted when doing things I don't care for.

I've said this before, but I really think it works... If you start a project and can't devote much time to finishing quickly then do at least one thing a night, it can be as big as cutting out a whole model or as small as installing a screw. One thing a night adds up and very soon you will be finished.

Ron
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Re: Modified SIG Twister

Post  Cribbs74 on Mon Oct 13, 2014 11:05 pm

JPvelo wrote:Looks good! I had to replace the leading edge stock in mine as well. I think the name "Twister" refers to the leading edge stock. I wish I would have sheeted  my leading edge.   I stretched my horizontal stab to 21" and it flies great.

Jim

Yeah Jim, the wood is questionable at best. Everything had a little bit of a warp to it and the cut pieces differ in shape and size.

Not, a show stopper, but annoying. I had built the wing in a hotel room and I thought that was what caused the twist. I didn't realize until after I got it home that the LE was warped. I now sight down all my straight pieces before gluing.
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Re: Modified SIG Twister

Post  getback on Tue Oct 14, 2014 8:02 am

Really Looks Good there Ron, That wing has got to be strong as it looks , A lot of dedication to the hobby to carry it to work with you Laughing Is this going to be a competition plane or just for fun ? Eric Very Happy
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Re: Modified SIG Twister

Post  Cribbs74 on Tue Oct 14, 2014 11:37 am

Trainer. Although if it's capable I'll have no problem flying competition with it.

Ron
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Re: Modified SIG Twister

Post  roddie on Tue Oct 14, 2014 6:59 pm

Cribbs74 wrote:Trainer. Although if it's capable I'll have no problem flying competition with it.

Ron

That's a great mind-set! You're already mentally set on "wringing-it-out"!!!!!!!
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Re: Modified SIG Twister

Post  Cribbs74 on Tue Oct 14, 2014 7:39 pm

Always!!!!

I don't get emotionally attached to these things. I want to have a couple planes in reserve.

My crash in Wichita, helped me to realize that you need more than one contest plane so when crap happens you are not out of the game.

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Re: Modified SIG Twister

Post  Cribbs74 on Wed Apr 22, 2015 2:16 pm

I am finally working on this thing again. Final sanded the fuse and purchased wood to do the block tips. Also recut the stab/elevator to 20'

I'll have pics up soon.
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Re: Modified SIG Twister

Post  RknRusty on Wed Apr 22, 2015 6:12 pm

Hi Ron
I'm glad to see you back on the build. So far it's a really nice looking plane. As you mentioned back in October, having a backup contest plane relieves some of the pressure. I'm really thin here, but have the best two that I have ever flown with the Oriental and the Ukey. And i know my club would give me a plane if I needed one. I hope you can get some good shop time to finish this one up. Any contests on your calendar?
Rusty

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Re: Modified SIG Twister

Post  Cribbs74 on Wed Apr 22, 2015 6:49 pm

So, here it is currently. I cut and installed the nacelle this afternoon. I've also resized the vertical stab.

I purposely made the horizontal stab/elevator larger, looks really big at the moment. Once I get the tips in place maybe it will look more the part.

4-40 threaded inserts.... Those little buggers really ticked me off. I drilled the holes to 11/64 like the package recommended and still managed to snap off the tabs while screwing them into the hardwood. Had to back them out using pliers so I'll have to pick up a new set. Not sure how to avoid that again. I even tried working them back and forth, still snapped off the tabs.





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Re: Modified SIG Twister

Post  RknRusty on Wed Apr 22, 2015 9:22 pm

These 4-40 inserts are the ones i use.

http://www.ebay.com/itm/NEW-Dubro-Threaded-Insert-4-40-4-391-NIB-/331333340920?pt=LH_DefaultDomain_0&hash=item4d25018ef8


They don't have any screwdriver tabs, you just run a bolt into it with a pair of lock nuts and crank it in with a good quality allen key. It takes a lot of force to crank them into the rock maple beams. I slightly over-drill or countersink the ply bearer so it doesn't crack while I'm installing the insert. On the Osprey I screwed the inserts all the way in flush with the face of the beam. But to do that I had to sleeve the bolt with a short piece of brass tube for the lock nuts to jam against so I could sink the inserts past the hole through the doubler. Once the glue is almost cured, a quick snap will release the bolt, or use heat if necessary. The bolt keeps epoxy out of the threads too.
Rusty

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Re: Modified SIG Twister

Post  pkrankow on Thu Apr 23, 2015 7:26 am

RknRusty wrote:These 4-40 inserts are the ones i use.

http://www.ebay.com/itm/NEW-Dubro-Threaded-Insert-4-40-4-391-NIB-/331333340920?pt=LH_DefaultDomain_0&hash=item4d25018ef8


They don't have any screwdriver tabs, you just run a bolt into it with a pair of lock nuts and crank it in with a good quality allen key. It takes a lot of force to crank them into the rock maple beams. I slightly over-drill or countersink the ply bearer so it doesn't crack while I'm installing the insert. On the Osprey I screwed the inserts all the way in flush with the face of the beam. But to do that I had to sleeve the bolt with a short piece of brass tube for the lock nuts to jam against so I could sink the inserts past the hole through the doubler. Once the glue is almost cured, a quick snap will release the bolt, or use heat if necessary. The bolt keeps epoxy out of the threads too.
Rusty

The ones with "screwdriver tabs" are not actually for a screwdriver. The tab is to provide relief so the chip formed by cutting into the wood has a place to go. These should all be installed using double nuts on a proper bolt or machine screw.
Phil
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Re: Modified SIG Twister

Post  Cribbs74 on Thu Apr 23, 2015 11:19 am

Thanks Phil,

Wish I had this info a day ago. Thing is the slot is cut into the top of the plug and not the bottom. So it has no effect on anything when they are beiing screwed into the bearers.

The bottom of the plug is tapered so I don't think I was installing them upside down.
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Re: Modified SIG Twister

Post  Ken Cook on Thu Apr 23, 2015 4:01 pm

I have used these in the past but I can't say I'm a big fan of them. In order to install them  you really are sacrificing a large hole through a 3/8" x 1/2" beam. Not only can this produce vibration issues but it can also lead to the mounts breaking in case of a mishap. Mishaps don't need to be accidental control inputs. A plane like the Twister can get real floaty when the engine quits especially if your on the windy side. A nose over like that can break your engine off if the mounts give way due to removing so much material. Just my opinion. Ken

Ron a #16 drill is probably a better bet due to it being slightly larger by about .005" over a 11/64" drill bit.
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Re: Modified SIG Twister

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