Twister - FINISHED, DONE, READY TO FLY!!!

[Rusty]

Thank you Dave and Dan.  I will be able to fly alone now. 

The Twister is coming along.  I got the wing, mostly finished.  I made a weight box and adjustable lead outs.  I found some nylon and made a guide.  I am happy with how it turned out.  I made the fuselage and added 2" to the tail, per Francher's plans.  I am going to put 1/4" tail feathers on it.   Today I was in the process of drilling the engine mount holes, when I discovered the FP 40 I am using has the bolt holes drilled out to 6/32.  I'm not putting that large of a bolt on it.  I will find another engine with stock bolt holes so I can use 4/40.   I will post pictures

[Dan McEntee]

Thank you Dave and Dan.  I will be able to fly alone now. 

The Twister is coming along.  I got the wing, mostly finished.  I made a weight box and adjustable lead outs.  I found some nylon and made a guide.  I am happy with how it turned out.  I made the fuselage and added 2" to the tail, per Francher's plans.  I am going to put 1/4" tail feathers on it.   Today I was in the process of drilling the engine mount holes, when I discovered the FP 40 I am using has the bolt holes drilled out to 6/32.  I'm not putting that large of a bolt on it.  I will find another engine with stock bolt holes so I can use 4/40.   I will post pictures

   If you can't find am acceptable replacement, see if you can bush the drilled out hole with a short length of 5/32" brass tubing. That had a 1/8" ID and a 4-40 screw should pass through that. If you can verify that the centers of the holes are accurate still, you could ream out the hole until the tubing fit snuggly and if there are any gaps, fill them with JB-Weld. Its a little work but worth it .
  Type at you later,
  Dan McEntee

[M Spencer]

How about Washers .!



Thisis wotcher need .  " Socket Shoulder Screws/Shoulder Bolts 4-40 X 1/4 (Pack of 500) "

Theres electronic ones too , shoulder / stepped bolts . We can start a new trend in engine mounting bolts . 



Or , Like E Says , throw a bitta brass toob onit .

[Rusty]

Thank you Dan and Mate Spencer,   I agree and have done exactly that.  McMaster Carr sells spacers that are perfect to bush down the 6/32 hole to a 4/40.  I bought about 12 of them years ago and fixed 3 engines.  However, the spacers are reasonable, shipping is not.  It is cheaper to get a good used crankcase.  I texted Bobby and he is going to send me one.  I have successfully got a solid bolt down by putting j b weld on the bolt using the theory Mate Spencer shows.  You put a washer on the bolt and put jb weld below it, the width of the mount lug.  When that dries, put the bolt in a drill and use a file to turn it down to the right size.  I have done it and admit it, even though I have been called a "red neck engineer" for it. However, I got credit with the man!  Recently, I sent him 4 brand new 15 engines to sell in his ebay store.  Right now I can get about anything he has listed w/o cutting back on my church offerings.

Addendum:  Dan, such is not the case here.  The holes are hogged out with a dremel tool.  They are elongated and enlarged.  The spacers I had would have fixed it as you say jb welding them in.   I have used brass tubing as you suggest also, when they are not that opened up.   What is the adjective you use to describe someone who ruins the lugs on a brand new engine?

[Rusty]

Okay, Guys; I have something to discuss and show.   I have the twister framed out and make as assessment of where I am in terms of success.

1)  I deem it right now a failure.
     A.  The plane weighs 38 oz and has no covering or paint.
     B.  The plane is very nose heavy.

2)  Construction.
     A.  The plane is Francherized, i.e. weight box, adjustable leadouts, 2" extended fuselage, reduced size rudder, enlarged flaps and elevator, 1/4" flaps and tail surfaces, carbon fiber pushrods and ball links on all ends. 
     B.  The plane has a OS FP .40 with tongue muffler.

3)  Correction.  (Input requested)
     A.  The nose will have to be shortened and the engine moved back.  How much??
     B.  To lighted the plane, I am thinking for using a 1" hole saw and cutting holes in the fuselage. How many and spacing?
     C.  The spinner can go.
     D.  The engine can be changed to a lighter one, but will that be needed?
     
4)  Where is Mate Spencer when you need him?

[Rusty]

picture

[Dan Berry]

Cover it, paint it, add the tailweight if needed and go fly it.

[Ken Culbertson]

1)  I deem it right now a failure.
     A.  The plane weighs 38 oz and has no covering or paint.
     B.  The plane is very nose heavy.

Not even close to a failure.  My Twister (in pix a few posts above) weighed in at 52 oz and balanced about 1" back from the LE.  It once put up a 535 in profile.  It has a very good airfoil and can easily carry the weight.  You are going to add 3oz (weight) of fuel and about 4-5 oz for finish.  Before you go cutting it up, take something that weighs about 1 1/2oz and put it on the wing at the flap line and see where it balances.  That is about where it will balance fueled.  The plans show the CG unfueled so do it again this time with 4oz on the wing TE.  Bet you are not still thinking it is nose heavy.

Some comments on lightening.  First, where does it balance "as is".  It should be at about the LE.  You could shorten the nose about 1/2" with out much difficulty but let's make sure you need to first.  I assume you have the wheels that far forward to fly in rough grass. You can save a bunch of weight with some lighter wheels and move them back about an inch.  If I remember right the wheel hubs on the plans are right at the LE, maybe a touch behind.   Same with the tank.  It is good to have it close to the engine but not critical.  That spinner looks huge.  If you get it covered and a few coats of dope on it and it still feels nose heavy, then is the time to start cutting.  If I remember the motor mounts are about 2 inches longer that the motor cutout.  That gives you about a half inch to play with.  The main reason I would be against cutting into the nose is that the motor mounts are the main transmitters of vibration to the rest of the fuselage.  Shortening them by moving the motor back may cause a vibration problem.  I stress "may".

Keep in mind that any weight you save aft or the intended CG will probably result in you having to add it back as tail weight and you have weakened the fuselage in the process.  Also keep in mind that the weight of these planes back when they were designed was to accommodate a Fox 35.  Todays motors are considerably more powerful.

Ken

[Rusty]

Not even close to a failure.  My Twister (in pix a few posts above) weighed in at 52 oz and balanced about 1" back from the LE.  It once put up a 535 in profile.  It has a very good airfoil and can easily carry the weight.  You are going to add 3oz (weight) of fuel and about 4-5 oz for finish.  Before you go cutting it up, take something that weighs about 1 1/2oz and put it on the wing at the flap line and see where it balances.

Some comments on lightening.  First, where does it balance "as is".  It should be at about the LE.  You could shorten the nose about 1/2" with out much difficulty but let's make sure you need to first.  I assume you have the wheels that far forward to fly in rough grass. You can save a bunch of weight with some lighter wheels and move them back about an inch.  Same with the tank.  It is good to have it close to the engine but not critical.  That spinner looks huge.  If you get it covered and a few coats of dope on it and it still feels nose heavy, then is the time to start cutting.  If I remember the motor mounts are about an inch longer that the motor cutout.  That gives you about a half inch to play with.  The main reason I would be against cutting into the nose is that the motor mounts are the main transmitters of vibration to the rest of the fuselage.  Shortening them by moving the motor back may cause a vibration problem.  I stress "may".

Ken

Thanks for the info.  I am going to move the engine back and reassess where I at.  I made the rudder adjustable.   With ball links the controls are amazingly smooth.

The maple mm beams are about 5 inches from nose. Somewhere I read the nose should be shortened, but plans did not call for it.   I agree moving tank back and losing spinner will help,

Thanks again

[Ken Culbertson]

It is a simple thing to Dremel out the back of the motor cutout without having to damage the doublers.  Do yourself a favor and leave the blind nuts in for the current hole settings and drill new ones.  When I did this kind of stuff I would plug the old holes with balsa so they wouldn't become fuel soaked and could be reopened easily. You just might want to move the engine back.  The plane is looking good.  One thing I noticed, and this is really personal preference, but I think the bellcrank to flap pushrod goes in the top hole of the flap horn on a Fancherized.  You are most likely going to need less flap movement than elevator and it will be easier that way.

[Rusty]

It is a simple thing to Dremel out the back of the motor cutout without having to damage the doublers.  Do yourself a favor and leave the blind nuts in for the current hole settings and drill new ones.  When I did this kind of stuff I would plug the old holes with balsa so they wouldn't become fuel soaked and could be reopened easily. You just might want to move the engine back.  The plane is looking good.  One thing I noticed, and this is really personal preference, but I think the bellcrank to flap pushrod goes in the top hole of the flap horn on a Fancherized.  You are most likely going to need less flap movement than elevator and it will be easier that way.

You don't miss anything, do you?  I struggled with that because the ball links (too large) will not allow me to locate them where it is specified.  To try and compensate for that I have the elevator in the most outside hole.   The twister plans and the francerized have them located opposite of each other on the flap horn.

I was thinking of moving the engine back to where the front lug bolt holes on the engine will use the back bolt holes on the plane.  That is moving it an inch or so.  What do you think?

[Dan McEntee]

   Even at 38 ounces as it sits, a typical finish for a model that Windy built in his videos was 10 ounces and that was traditional dope finish with lots of clear. Even if you did that it would be 48 ounces and that would still be a pattern capable airplane. If you go iron on covering for the wing and tail and spray can for the fuselage, you might be 5 to 7 ounces more. Well within the "I'll take it!" range!!  Resist any temptation to cut anything until you relocate your engine and such. Keep in mind that adding any finish to the tail end has more effect that the rest of the airplane as far as balance. Look at the airplane from the top and notice how much of the finish, including iron on covering, will be behind the main spars!! That means behind the balance point. Don't put the cart ahead of the horse!! A bare bones airframe will be nose heavy with the engine and tank installed.
   The only things I might have cautioned you on was replacing the balsa spars with spruce but that wasn't much of a penalty, and not cutting out the ribs in the outboard wing like you did the inboard. Lots of airplanes wind up having too much weight out there even before the tip weight is added. I have learned to build a model where it is balanced on the roll axis if it has equal length wings. If it was something with 1 to 2" of inboard wing offset you could stand the weight better. If everything is aligned correctly, that's the first thing you want to achieve and the most important. Just do your final sanding after moving the engine and re-evaluate. I think you are going to be just fine.
   Type at you later,
   Dan McEntee

[M Spencer]

Youll Need To . If you put the S T .60 in it .        

Um . Mounting Plates . steel or ally , under the lugs . Tapered for offset if reqd. Spead the load . and you fill the old ( engine ) holes with ayrldite 7 file flush , when youve made up your mind !

Acly , Steel Plates say 10 x 30 metric things , drilled & tapped ( steel ) woukld spead the nut load too . CRUSHIBNG soft bearers is a bear . But Heart Oak / Maple should take it .
Weve spliced new fronts on a bearer or two . When neccesary .

MOVINGIT .

Put the C G onnit . Pull the motor back & forward. Use a elestic band . or masking tape . with the b great 3030 muffler , Itll need to go back . but Id still have it 1/4 forward . Of the plan C G .
the Tower .40 mufflers the samme . But HALF the WEIGHT .

As in use a soft pencil / marker pen , put a line under on the c.g. , or on a bit of tape . Balance on someting under each side . If it falls fwd Yr o.k. , if it falls back , yr not .

[Brett Buck]

Thanks for the info.  I am going to move the engine back and reassess where I at.  I made the rudder adjustable.   With ball links the controls are amazingly smooth.

The maple mm beams are about 5 inches from nose. Somewhere I read the nose should be shortened, but plans did not call for it.   I agree moving tank back and losing spinner will help,

Thanks again

    Don't do anything until you have at least most of the finish on it. Almost all the finish will be behind the CG, so will move it back.

        Brett

[Ken Culbertson]

The twister plans and the francerized have them located opposite of each other on the flap horn.

Nothing wrong with that.  It is better than having ball links colliding.  With that arrangement you pick the hole that will give you the desires flap movement.  Mine was set to 30 degrees each way.  Then you use the elevator horn to give you whatever you want.  It should be more than the flaps.  Mine was 40.  That is a lot more than you need but it is the ratio that matters.  I really wish you would hold off on the cutting the nose until you get the majority of the finish on.  If you do need to move it, it is best to know exactly how much.

Ken

[Rusty]

Guys, I pulled the trigger and did it.  I moved the engine back to where the front holes in the engine bolt to the rear holes on the fuselage.  It went very quickly with my Craftsman scroll saw.  I cut the fuselage front off the same clearance behind the thrust washer as was before.   I put everything back on, but the spinner.  Can you believe it balances PERFECTLY about 3/16 in front of the spar, where the plans call for.   Man, I never imagined this would be so easy,.  The plane is now 35 oz and change. 

As Gomer said, thank you, thank you, thank you.   I'm back in the ball game.

Rusty

[Ken Culbertson]

Guys, I pulled the trigger and did it.  I moved the engine back to where the front holes in the engine bolt to the rear holes on the fuselage.  It went very quickly with my Craftsman scroll saw.  I cut the fuselage front off the same clearance behind the thrust washer as was before.   I put everything back on, but the spinner.  Can you believe it balances PERFECTLY about 3/16 in front of the spar, where the plans call for.   Man, I never imagined this would be so easy,.  The plane is now 35 oz and change. 

As Gomer said, thank you, thank you, thank you.   I'm back in the ball game.

Rusty

With no finish it should be about on the LE.  You are going to be terribly tail heavy.

Ken

[Rusty]

Dan, the Fancherized Twister has spruce spars. 

[Rusty]

With no finish it should be about on the LE.  You are going to be terribly tail heavy.

Ken

Okay.  Being that I did not drill any new holes, I can move it forward.  There is plenty of room to do that.  I will move on the covering it and putting some dope on it.   I will drill the final motor mount holes when I have it covered and painted. 

Thanks

[Rusty]

Okay.  Being that I did not drill any new holes, I can move it forward.  There is plenty of room to do that.  I will move on the covering it and putting some dope on it.   I will drill the final motor mount holes when I have it covered and painted. 

In fact, I could use the original holes if needed. 

Thanks

[Brett Buck]

Okay.  Being that I did not drill any new holes, I can move it forward.  There is plenty of room to do that.  I will move on the covering it and putting some dope on it.   I will drill the final motor mount holes when I have it covered and painted. 

Thanks

   Just finish it, and see where it comes out, add weight if necessary.

     Brett

[Rusty]

Okay.  Thanks Brett.

Please see what I did.

PS: Ken what do you see wrong with the engine?

[Ken Culbertson]

Okay.  Being that I did not drill any new holes, I can move it forward.  There is plenty of room to do that.  I will move on the covering it and putting some dope on it.   I will drill the final motor mount holes when I have it covered and painted. 

Thanks

By jove I think he's got it. 

Ken

[Dan McEntee]

Dan, the Fancherized Twister has spruce spars.

     Well it's not a big deal but look at the plan again. You can reshape the nose a bit now also. What size spinner was that yellow one you had on there?  I usually stick with a 2" or less spinner and a Tru-Turn or Great Planes aluminum spinner will have a flat backing plate that will fit easier. SIG plastic spinners had a flat back plate also if you have any of those laying around. The DuBro and Goldberg brands have that offset that has to be allowed for. A 2" spinner will let you use a starter if you want/need to, blend in nicely at the nose, and not be too heavy. An aluminum hub nut like the Higgley unit is a good substitute.

    Have fun!
  Dan McEntee

[Trostle]

Okay, Guys; I have something to discuss and show.   I have the twister framed out and make as assessment of where I am in terms of success.

     B.  To lighted the plane, I am thinking for using a 1" hole saw and cutting holes in the fuselage. How many and spacing?
   

Cutting holes in the fuselage will not save you much weight.  I just cut a 1" disk from the heaviest 1/2" sheet balsa I have.  (It has to be the hardest and heaviest piece of balsa that I have ever had, at least 10# wood, probably a lot more - it has been in my stash for more than 50 years.)

The weight of this 1" disk is 0.9 grams.  If you cut 7  1" diameter holes from this heavy piece of wood, you would save all of about 1/4 ounce.

Keith