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Hot Topic (More than 10 Replies) Bristol Beaufighter (Read 243 times)
Sky9pilot
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Re: Bristol Beaufighter
Reply #16 - Jan 6th, 2022 at 2:27pm
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To mount the motors to the dowel through the fuselage would seem to require access somehow to the dowel either through the bottom or top by leaving the tissue off or some kind of removable hatch to me.  But being this is a peanut weight is a concern with a hatch. 

I believe the FACN had an article on using plastic straws to make motor bobbins/spools by melting the ends making them look like small spools.  Don't know if that would work for you in this setting. Maybe making the ends of the motor easier to handle.
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alfakilo
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Re: Bristol Beaufighter
Reply #15 - Jan 5th, 2022 at 2:30pm
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The "V" motor technique is tricky on something this small. I'm using a large paper straw as a 'blast tube' and aligning it with the prop shaft is proving a challenge. If this becomes impractical, I can always route the motor straight back to the trailing edge. Or not use a blast tube.

The rear motor mount remains an unsolved problem. The plan seems to show a typical dowel running thru the fuselage. I'm not sure how to mount two motors to that and I could really use some suggestions!!
  

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Re: Bristol Beaufighter
Reply #14 - Jan 2nd, 2022 at 6:02pm
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AK, good looking set of bones.  This bird always looked like a real challenge to me. That's why I never built it I guess.  I look forward to your solutions.
  

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alfakilo
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Re: Bristol Beaufighter
Reply #13 - Jan 2nd, 2022 at 10:59am
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Thanks, Mike! Good info for everyone.

Here's the lash up as I continue work on the nacelle area. Didn't like the 1/32" wrapped idea in the plan. This thing is small, don't know if I'm going to be successful at getting the motors from the nacelles to the fuselage. Maybe use paper soda straws to house the rubber. Fun build but I think a dimer or bigger would be a lot less hassle.
  

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Re: Bristol Beaufighter
Reply #12 - Jan 2nd, 2022 at 8:41am
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alfakilo wrote on Dec 31st, 2021 at 8:15pm:
Sky9pilot wrote on Dec 29th, 2021 at 7:13pm:
...To adjust the thrust for right and down thrust...


It looks like that drive plate screw is in the upper right (1:30 clock position viewed from the rear) side of the nacelle. Does that mean that when it is screwed in that the thrust line is moved down and to the left?


Mike Midkiff helped me trim my Tigercat - his advice for twins was to adjust downthrust only. He indicated side thrust adjustments were ineffective.  To induce (or tame) a turn under power, add more downthrust to the prop on the inside of the desired turn.

For a lightweight, deterministic thrust adjuster on a small twin, put a screw in the top center of the drive plate and a strip of 1/16" square across the lower portion of the thrust plate.  Turning the screw will allow fine adjustments to the thrust angle.

Really enjoying following your build.

Mike
  
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Re: Bristol Beaufighter
Reply #11 - Jan 1st, 2022 at 1:26pm
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alfakilo wrote on Dec 23rd, 2021 at 11:25am:
This thing is tailor made for frustration!! I'm using 1/32" formers and 1/20" stringers for the fuselage, so far not too much damage done!

The fuselage is pretty straight-forward, but the wing is going to be a challenge if I stick with the "V" motor idea.


When I use the "V" motor in a multi I put rather robust diagonal bracing (maybe unnecessarily too robust) in wing center section.  Your Peanut scale Beaufighter with very light structure and probably no motor heavier than 1/16" can have lighter diagonals. The examples in the photos are Giant NoCals.
  

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alfakilo
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Re: Bristol Beaufighter
Reply #10 - Dec 31st, 2021 at 8:15pm
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Sky9pilot wrote on Dec 29th, 2021 at 7:13pm:
...To adjust the thrust for right and down thrust...


It looks like that drive plate screw is in the upper right (1:30 clock position viewed from the rear) side of the nacelle. Does that mean that when it is screwed in that the thrust line is moved down and to the left?
  
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Re: Bristol Beaufighter
Reply #9 - Dec 31st, 2021 at 3:07pm
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A caution on twins or any multi-motor rubber powered model, a little bit of thrust line adjustment goes a LONG way!  This is especially true the smaller they get.

KF
  

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Re: Bristol Beaufighter
Reply #8 - Dec 29th, 2021 at 7:13pm
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AK that's exactly what it is.  To adjust the thrust for right and down thrust or the opposite thrust in the opposite nacelle when building twins.
  

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alfakilo
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Re: Bristol Beaufighter
Reply #7 - Dec 29th, 2021 at 5:22am
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I'm putting the center wing section together now and trying to figure out what Towner had in mind. Would like to know if he actually built this.

For example, he shows a "drive plate" set into the nacelle opening. Not sure what this does. Maybe a way to adjust thrust line?
  

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Re: Bristol Beaufighter
Reply #6 - Dec 28th, 2021 at 10:31pm
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The V thing works but you have to use short motors or braid the motors to keep the balance from shifting to the tail as they unwind.  Haven't tried it on anything as small as a peanut.

KF
  

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Re: Bristol Beaufighter
Reply #5 - Dec 24th, 2021 at 3:09pm
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Looking good AK!  The Beaufighter is such a neat airframe - has the same sort of pugilistic character as the Grumman Skyrocket.  Unlike the Skyrocket it has a combat record worthy of a thousand stories.

Look forward to watching this model come together.

Mike
  
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alfakilo
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Re: Bristol Beaufighter
Reply #4 - Dec 24th, 2021 at 10:38am
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Fuselage more or less done. I added the dorsal bubble that was missing in the plan.

You can see the two built up formers that I think helps me keep things lined up in the initial frame-up. I'll remove the extra wood later.
  

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Re: Bristol Beaufighter
Reply #3 - Dec 23rd, 2021 at 12:08pm
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Alright AK...
I shall follow this build closely.  I've looked at that plan several times.  I've heard that you need a good strong prop shaft and close fit to bushing to avoid binding of the shaft due to the "V" tension of the rubber on the shaft.  Best of luck with this baby!
  

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Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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alfakilo
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Re: Bristol Beaufighter
Reply #2 - Dec 23rd, 2021 at 11:25am
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This thing is tailor made for frustration!! I'm using 1/32" formers and 1/20" stringers for the fuselage, so far not too much damage done!

The fuselage is pretty straight-forward, but the wing is going to be a challenge if I stick with the "V" motor idea.
  
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