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Author Topic: Miss Canada Misbehaving  (Read 920 times)
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randoloid
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« on: October 18, 2016, 01:56:10 PM »

I hoping someone can give me some insight on what's going on with my Ms Canada (36" span by Easybuilt).  I'm using a Superior 12" balsa prop and 6 strands of braided 1/8 Rubber
Nose block has almost 7 degrees down thrust and 4 degrees right

I've trimmed to where it has a decent glide now and it flies pretty well on low power flights of around 100 turns.  But when I increase to 200 turns the climb rate flattens to almost zero - increasing to 300 turns the climb becomes a dive.  I've never experienced this before and I'm scratching my head as to how to fix.

any insight most appreciated.

Thanks
r

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DerekMc
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« Reply #1 on: October 18, 2016, 02:02:19 PM »

7 degrees downthrust sounds like a lot to me. I would take some out and see what happens.
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« Reply #2 on: October 18, 2016, 02:03:22 PM »

Well, I'll jump in before the experts arrive and suggest that's far too much down and sidethrust. I don't know the model - high wing monoplane? - but maybe start with zero down and 2 degrees right?
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applehoney
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« Reply #3 on: October 18, 2016, 03:02:48 PM »

Agree with Bill and Derek re thrustline.    Check your wing/stab decalage too.

By the way 6 strands of 1/8th is too small a motor for a Miss Canada
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randoloid
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« Reply #4 on: October 18, 2016, 03:10:35 PM »

Yes high wing... see it here.  http://www.easybuiltmodels.com/ff11.htm


Agreed that seems rather extreme angles and I actually started out with zero for down / side thrusts, then made a new NB after shimming to those specs.

I'd built this model before and didn't have issues trimming. This is a new fuse built after a crash- and obviously there's something out of spec with this one.  

While I'm not against re-building another fuse It's now become a personal challenge to make it fly!
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randoloid
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« Reply #5 on: October 18, 2016, 03:11:38 PM »

Oh and the motor size was a typo-  should be 16 strands 1/8
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calgoddard
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« Reply #6 on: October 18, 2016, 03:17:11 PM »

Note: the following reply was written before I read Reply #5. It was being written at about the same time I was writing the text set forth hereafter.



I agree with the comments above.  7 degrees down thrust is way too much and probably killing the climb of your model.

4 degrees of right thrust is probably too much as well.  I have had problems with too much right thrust.  Depending on the model, 1 - 2 degrees right thrust should help prevent a power stall (along with down thrust) and put the model in a nice right turn.

When I read the size of your rubber motor I immediately thought it sounded way too small for an airplane with a 36 inch wing span.

I checked my list of recommended motors for Old Timer and Nostalgia rubber airplanes.  For Miss Canada Sr. it recommends a 12 x 1/8 inch cross section and 42 inch motor length.  It's a big model.  
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Hepcat
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« Reply #7 on: October 18, 2016, 08:37:17 PM »

I think the problem may be that your CG is too far back.  This means that when you did your hand glide testing that you would have to reduce the incidence difference between the wing and tail(decalage) to get a good glide.  Under low winds this may works but as you put in more winds the aeroplane will fly faster and and start to nose down, when it will fly even faster and more nose down until it dives steeply into the ground.  It would be almost impossible for the downthrust to cause such a dive in on its own because the increase in speed from downthrust, if the CG and decalage were correct, would actually increase the wing lift and make the model nose up.  So, check the CG (please let us know what it is for interest), retrim the glide and remove the, apparently, accidental downthrust.
John.
    
« Last Edit: October 18, 2016, 08:48:58 PM by Hepcat » Logged
randoloid
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« Reply #8 on: October 18, 2016, 08:52:47 PM »

Thanks for the advice John,

That sounds like a logical diagnosis to me- When setting the CG I felt it seemed too far back-  I actually couldn't find any notations for CG on my plan -- someone had told me it could vary anywhere between 65-75% of Chord-- If I remember correctly I'm at 70 percent.
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« Reply #9 on: October 18, 2016, 09:05:26 PM »

Note: the following reply was written before I read Reply #5. It was being written at about the same time I was writing the text set forth hereafter.



I agree with the comments above.  7 degrees down thrust is way too much and probably killing the climb of your model.

4 degrees of right thrust is probably too much as well.  I have had problems with too much right thrust.  Depending on the model, 1 - 2 degrees right thrust should help prevent a power stall (along with down thrust) and put the model in a nice right turn.

When I read the size of your rubber motor I immediately thought it sounded way too small for an airplane with a 36 inch wing span.
Oh and the motor size was a typo-  should be 16 strands 1/8model

Rando,

Thrust adjustments are a definite issue, start over using the suggestions by others.

I would ask a couple of other questions here: (Not in any particular order)

1) 16 strands of 1/8th x how long?

2) C/G location?

3) Purchased 12" prop, (What pitch is it?)

Otf'er....

« Last Edit: October 18, 2016, 09:59:05 PM by Oldtime Flyer » Logged
Maxout
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« Reply #10 on: October 19, 2016, 09:02:08 AM »

Thanks for the advice John,

That sounds like a logical diagnosis to me- When setting the CG I felt it seemed too far back-  I actually couldn't find any notations for CG on my plan -- someone had told me it could vary anywhere between 65-75% of Chord-- If I remember correctly I'm at 70 percent.

Try coming forward to 60%. I seem to remember that's where mine was, and it was a reasonably good flier. Would have been better if I had been able to carve decent propellers at the time.
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« Reply #11 on: October 20, 2016, 01:33:07 AM »

Thanks for the advice John,

That sounds like a logical diagnosis to me- When setting the CG I felt it seemed too far back-  I actually couldn't find any notations for CG on my plan -- someone had told me it could vary anywhere between 65-75% of Chord-- If I remember correctly I'm at 70 percent.

Try coming forward to 60%. I seem to remember that's where mine was, and it was a reasonably good flier. Would have been better if I had been able to carve decent propellers at the time.


As Josh stated in his last post, 60% would be a good C/G to start your re-trimming efforts.

Otf'er..........
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randoloid
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« Reply #12 on: December 28, 2016, 01:44:01 PM »

Thanks to everyone for the input.  Attached are photos of my solution.  Never could get that one to fly... pretty sure there was something askew with the fuselage so I just built another.... and not just the fuse, I built from the ground up just to be safe!  Very happy with the finished product.  still have windows to add but she weighed in at a respectable 69.2g that's everything but the motor.

Will report back when she see's the air.

Attached files Thumbnail(s):
Re: Miss Canada Misbehaving
Re: Miss Canada Misbehaving
Re: Miss Canada Misbehaving
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« Reply #13 on: December 28, 2016, 01:54:36 PM »

Thanks to everyone for the input.  Attached are photos of my solution.  Never could get that one to fly... pretty sure there was something askew with the fuselage so I just built another.... and not just the fuse, I built from the ground up just to be safe!  Very happy with the finished product.  still have windows to add but she weighed in at a respectable 69.2g that's everything but the motor.

Will report back when she see's the air.



Very nice randoloid. Look forward to flight reports.

Otf'er.......
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Balsa Ace
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« Reply #14 on: December 28, 2016, 02:43:37 PM »

She looks great,Randoloid.

Scott
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Bargle
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« Reply #15 on: December 29, 2016, 08:34:58 PM »

Looks great, Randoloid. Should fly fine at that weight. Looking forward to your report.
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crashcaley
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« Reply #16 on: December 29, 2016, 10:18:02 PM »

Very nicely built, and great weight to boot.  I hope it flys as well as it looks.  Caley
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What's stall speed?  Undecided
Maxout
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« Reply #17 on: December 30, 2016, 07:11:51 PM »

Tech colors I see! Shoulda gone orange and purple. Tongue

Seriously though, looks great and no reason it shouldn't fly well too.
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randoloid
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« Reply #18 on: April 17, 2017, 12:08:22 PM »

Oh what a happy day.  Finally, I have my Miss Canada flying!  It took me long enough-  I think I rebuilt all or portions of this model 4 times. I am not the greatest builder, I'll admit, but what I lack in experience and ability I make up for with stubbornness!

Saturday I logged a flight of right about 2:30 with 1,000 turns-  Using 8 strands of 1/8 at about 30" length (braided)-  So it's got plenty more to give!

My brother video'd the flight-  not great- he tries to walk and keep it in frame which is never a good idea,  but hey it's proof that it flies!  https://www.youtube.com/watch?v=VffkGloe19o
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crashcaley
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« Reply #19 on: April 17, 2017, 01:49:10 PM »

Very nice flight.  Glad to see you finally got it tamed.  Caley Ann
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What's stall speed?  Undecided
FLYACE1946
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« Reply #20 on: April 30, 2017, 10:35:07 PM »

That is a real flyer and I hope you can keep it for a while. These can easily fly for a very long time. GOOD FOR YOU.
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