After much cogitation over which model to focus on next, decided to have a run at the partially completed Avro Anson which has been waiting in various corners for nearly two years for some of Frank's "it will complete itself" magic.
Since the Anson is not as well known as other Avro aircraft such as the Lancaster, the Arrow and the Vulcan, a little about the aircraft I'm trying to model.
First built in the mid 1930's, the Anson was the first RAF aircraft with retracts. (Damned retracts have been frustrating modellers ever since!) Conceived as a light bomber, it was rapidly outclassed by other new aircraft in that role but because of its stable, gentle flying characteristics made an excellent twin engine and navigation trainer.
Several variations were produced and my Dad flew two of them, Anson IIs and Anson Vs as part of the WW II Commonwealth Air Training Plan out of Somerside PEI.
The ones Dad flew were yellow, lacked the greenhouse window treatment, the turret and the blistered cowling of the Anson I ...I'm still not sure which way to go with the model...Anson I or II...definitely not a V which has a different shaped fuse. I can make that decision later.
First two pics are I's, last two are II's. The picture of the Anson being moved was taken in Nova Scotia recently and I'm still researching to find out if the aircraft pictured is being repaired to airworthy condition. We have one Anson V in the Canadian Warplane Heritage Museum collection in Hamilton, but it's outside, in sorry shape and unlikely to ever fly again.
Pictures below...I'll post about the model itself when I get a minute...have to go play Monopoly with my newly inherited grand-daughters while they're here visiting as part of the seasonal insanity.
Very eclectic choice! Looking forward to photo day!!
Andy
Okay,...the model to date...
In the beginning...
For the last several years, my Dad and I met weekly for lunch at his local pub to discuss airplanes, full size and model. The WW II airplanes he flew were often the focus.
"I'd like to build an Anson model" he announced at one lunch in late 2012.
"Okay, if I can find one, I'll build the wing, you build the rest", I answered...silly me!
...and so began a three month search for a suitable Anson model...
The Traplet/Hutson Anson
From Traplet Publications in the UK, we bought; a plan drawn by Duncan Hutson, a wood kit of laser cut balsa and lite ply and plastic cowlings, turret, windshield and underside tail fairing. The model is about 85" wingspan and designed for two .30 glow motors. Even with the laser cut wood and thermo vacuum formed plastic, this is not a beginners' build...so why try it? It was the only Anson kit we could find!
The Retracts
Functional scale retracts for models of WW II aircraft are a challenge...the Anson is no exception.
The plans show a builder constructed scale retract system...which a skilled machinist or model engineer could build, but which I couldn't.
So, another internet search resulted in a set of retracts for a 103" DC-3. These were close in the mechanism operation and in size but silly expensive...but I've already identified silly me and I bought them.
They sat for two years in the basement and when I first plugged them in....sizzle...burnt plastic smell...smoke, unplug too late, and poof, the retract controller was toasted!
They're going back to an outfit called Century Jets in the US for a complete rebuild...silly expensive just got ridiculously silly expensive!
I'll finish the post tomorrow...seasonal fatigue is overcoming insomnia!
Couldn't help but check out the Traplet and Century Jets web sites. Very impressive. I was particularly impressed by the Traplet video featuring Barry Atkinson doing a walk through of their wood packs and their laser cutter. That is SO seductive. Excellent quality, and the time saving on the wood packs makes you want to cry. And for the price of the Century Jets retracts you can almost buy yourself a used (full-scale) Cessna! Very high end. ;D
I'd be really interested in knowing two things:
1. what went wrong when you powered up the retracts;
2. how you could restrain yourself from playing with them as soon as they arrived, as opposed to waiting fro TWO years!!
Good luck on the build. It should be a fantastic work of art when you're done, and a really fine tribute to your dad.
Cheers.
Andy
Hey Bill,
This will be a fantastic model. Good luck with the build.
I recall you saying the retracts worked in reverse from what you really need. Is there any change that while they are rebuilding the retracts, they can reverse the function?
Quote from: piker on December 28, 2015, 10:47:56 AM
Hey Bill,
This will be a fantastic model. Good luck with the build.
I recall you saying the retracts worked in reverse from what you really need. Is there any change that while they are rebuilding the retracts, they can reverse the function?
What novel idea - gear down for in-flight, gear up for take-off and landing. These would be perfect for Frank!! ;D
Andy
Quote from: Andy Hoffer on December 28, 2015, 11:56:45 AM
Quote from: piker on December 28, 2015, 10:47:56 AM
Hey Bill,
This will be a fantastic model. Good luck with the build.
I recall you saying the retracts worked in reverse from what you really need. Is there any change that while they are rebuilding the retracts, they can reverse the function?
What novel idea - gear down for in-flight, gear up for take-off and landing. These would be perfect for Frank!! ;D
Andy
Andy, err, Frank?
Up tidilly up, up for flying and down tidilly down, down for landings and take-offs...even the retracts I have (ESMs)are designed that way...and Rob, contrary to what I'd been told, the mechanisms on a DC-3 and an Anson work the same way,...the front legs scissor forward around the rear radius rod, so using DC-3 gear on an Anson is fairly scale...turns out the difference is that the upper part of the legs pivot 180degrees on an Anson whereas my ESM DC-3 retracts only drive the upper part of the leg 90degrees. Retract photos below are worth a lot of words.
Andy, the retracts (ESMs to be rebuilt by Century Jets) themseves work okay plugged directly to a battery, but the controller (the retracts use their own battery) blew up first plug in! Way too much going on in my life last two years to open all the toys when the mailman brought 'em and the retracts waited nearly two years.
First photo shows Down, tidilly, down, down (landings and take-offs) and second shows Up tidilly up,up(flying)
Wheels are 4"...added Ed's size gauge for reference...see Ed? You left your mark on TEMAC in many ways!
The second photo shows the twisted and warped case of the retract controller unit...a real stinker!
Dad framed up the fuselage and empennage at least a year ago and now it's up to me to complete the model. He and I talked about using foam as part of the build and he used it for the elevators and the leading edge of the rudder. Ed's size reference looks a bit lost in the fuse...I was tempted to use a six pack!
Wow. That is going to be some big plane. Looking like a great project.
;)
Happy New Year anyone who's reading!
Woke up early this morning and ordered the blistered cowls from Traplet, so, Anson Mk I it is.
The Traplet plan is for a wet fuel power system and custom fabricated retracts. I'm electrifying(the model) and using ESM retracts.
Those choices necessitated a re-thinking of the nacelles...and using other people's ideas for the rest of the wing.
RCGroups has an excellent build thread for this model, started by Pat Lynch, an Aussie who is a museum quality model builder, machinist, model engineer...http://www.rcgroups.com/forums/showthread.php?t=1817579
I am simply hoping to build something which captures the character of the real airplane and flys well but I am using Pat Lynch's ideas throughout my build...including the decision to split the 2100mm(7') wing into three pieces.
The wing centre section will extend out to the flap/aileron split making it about 1000mm (40"). Plan is for this section to carry the motors, batteries, ESCs, retracts, flap servos and receiver.
The Traplet wood kit should include two 1/8" main spars which are laminated to form a 1/4" spar. I could only find one and had to cut a new 1/4" main spar. I'm using Traplet's drag spar.
Below are photos of the centre section test fitted so I can understand how all the bits go together.
Bill,
I looked everywhere on photo of this morning's post but could not find a single beer bottle ...anywhere.
You either have this project under control or you have completely lost it.
Frank
ps: the wing centre section looks great.
Since my retracts are different from the ones called for on the plans, I've re-designed the retract mounts/ motor mounts. Each engine/retract bearer will consist of two 1/8" ply extended "ribs" with a 1/4" ply plate between them and a 3/16" ply firewall.
So far I've cut and test fitted the extended ribs...the nacelles and therefore the "extended" part of the engine bearing ribs are inclined down about 4 degrees from the wing chord which will provide down thrust.
Next, I'm going to build a jig for all these bits to check and hopefully keep everything aligned...
Frank, my world is back to normal...see the photo...
Mr. Nutz,
re:"Frank, my world is back to normal...see the photo..."
Glad to see you are feeling fine and discretely hiding the frustration indicator in the top left hand corner of the photo. ;D
Frank
Quote from: Frank v B on January 05, 2016, 07:34:35 PM
Mr. Nutz,
re:"Frank, my world is back to normal...see the photo..."
Glad to see you are feeling fine and discretely hiding the frustration indicator in the top left hand corner of the photo. ;D
Frank
Three bottles hardly captures the frustration of trying to get things to line up. Using the laser cut ribs and my home made main spar, things weren't bad but adding two friction fit engine-bearer ply ribs on each wing and tying to avoid twist in the wings has been a fiddly business. Time to jig it all or..."the jig's up!"
Great work, Bill.
It'll get easier once everything is secured and in the right place.
It's look really good so far!
Bill,
re: your "Three bottles hardly captures the frustration of trying to get things to line up."
OK. Cue the two-four!
Frank
Made a crude jig to check the alignment of the wing centre section. Last time I tried to build a tapering semi-symmetrical wing was before I attended TEMAC build classes and I ended up cutting the bottoms off of all the ribs, building it on a flat surface and gluing the rib bottoms back on afterwards.
Think I've learned something at build classes and I'm gonna try this one "off the board"
Laser cut ribs make life a lot easier. I still feel better jigging the whole thing before anything gets glued. My crude jig consists of a 2" sheet of pink foam, slotted white foam sheets to hold the spars level at the centre, equal height foam blocks just inside rib 6 and squares to get the engine bearers vertical once the spar centre is horizontal.
Frustration index down to two Canadians today...saving the two-four for a bad day!
I have some more beer in the fridge so if any of you experienced builders see potential potholes, LMK...I'm not against opening another...or two.
The folks at the Boeing plant in Seattle will be envious!! ;D
Andy
Quote from: Andy Hoffer on January 10, 2016, 07:45:48 PM
The folks at the Boeing plant in Seattle will be envious!! ;D
Andy
Andy, you're right! I can wash down the balsa dust as I'm working...the Boeing crew doesn't even have balsa dust or balsa dust throat soother and I'm glad they don't...I fly in one of their airplanes from time to time!
Had to see how the wing and fuse will go together...something to do while I make the final decision on how to make the wing outer sections removable. Once I start gluing, options for removable sections get stickier ::)
Plan calls for a one piece wing of just over seven feet and a fuse just over six feet. Since I would prefer not to separate wing and fuse for transport...wait a minute...if all the electrics except the rudder and elevator servos are in the wing...maybe separating for transport wouldn't be all that bad...now, will a seven foot wing fit imy Escape?
Glad I wrote this...made me do some thinking!
I see it is a true "Canadian" twin, now!!!!
Hey Bill. I like the twin power ;D
As we discussed last night, I found removable tips to work well, but they add an extra challenge while building, probably more weight with less strength, and unsightly seams in the wing. IF you have enough length in your vehicle for a one piece wing, I would always suggest that route. The exception being where the wings plug into the fuselage from either side. The fuselage WITH a 4' wing root still attached, will take up more space than a one piece wing laying along the side of the fuselage.
I know you were thinking that keeping the center section on the plane would simplify assembly, but as you point out, everything BESIDES the tail servos can be fastened to the wing and go with it when removed with only a simple disconnect of a couple of servo wires. That's how my two, multi motor flying boats are set-up. I leave 6" extensions plugged into the servo Rx for easy plug ins.
Quote from: sihinch on January 13, 2016, 05:50:49 PM
I see it is a true "Canadian" twin, now!!!!
Definitely Canadian powered!
Quote from: piker on January 14, 2016, 10:29:49 AM
Hey Bill. I like the twin power ;D
As we discussed last night, I found removable tips to work well, but they add an extra challenge while building, probably more weight with less strength, and unsightly seams in the wing. IF you have enough length in your vehicle for a one piece wing, I would always suggest that route. The exception being where the wings plug into the fuselage from either side. The fuselage WITH a 4' wing root still attached, will take up more space than a one piece wing laying along the side of the fuselage.
I know you were thinking that keeping the center section on the plane would simplify assembly, but as you point out, everything BESIDES the tail servos can be fastened to the wing and go with it when removed with only a simple disconnect of a couple of servo wires. That's how my two, multi motor flying boats are set-up. I leave 6" extensions plugged into the servo Rx for easy plug ins.
I agree with everything above...however, my daily driver would be hard pressed to carry a seven foot wing. But, I haven't given up on the idea of one piece wing...so nothing's glued...yet...
Test fitted ribs 7-15 on the left wing. If the wing becomes three section, the break will be at rib 10, (flap/aileron intersection) ...so plan is, the carbon tubes can remain one piece, or act as sleeves if the wing is split into three pieces, with an inner carbon tube transferring load from the outer wing to centre section.
Challenge was to get a friction fit hole for the carbon tubes and have the laser cut ribs line up to create 2 degrees washout at the tip. Washout starts outside the nacelles and I set things up to create 1 degree washout at rib 15.
Jigged the ribs on a piece of 2" pink foam, and sharpened a piece of brass tubing to cut the holes...
Ended up re-drilling the drag spar holes. The hole for the tube was too close to the slot for the 1/4" square spar and the ribs split as they were fed on to the carbon tube.
Will bring the wing to class to get some advice tonight.
Cool!
Did you sharpen the brass tube before drilling? If "yes", did you sharpen/taper on the outside of the tube? If "yes", the act of sharpening on the outside creates a smaller diameter hole cutting edge, with the area further up to tube at the original outside diameter. As you plunge the brass tube further into the hole the larger diameter forces the wood away, causing the split. Is that what happened?
Best option, is to taper on the inside of the tube. It won't split the ribs, but it jambs the blanks in the tube pretty good. I find I can't cut through vary many layers without stopping, removing the tube from the drill press, and clearing the blanks from the tube by pushing them out from the other end.
Quote from: piker on January 21, 2016, 10:43:16 AM
Cool!
Did you sharpen the brass tube before drilling? If "yes", did you sharpen/taper on the outside of the tube? If "yes", the act of sharpening on the outside creates a smaller diameter hole cutting edge, with the area further up to tube at the original outside diameter. As you plunge the brass tube further into the hole the larger diameter forces the wood away, causing the split. Is that what happened?
Best option, is to taper on the inside of the tube. It won't split the ribs, but it jambs the blanks in the tube pretty good. I find I can't cut through vary many layers without stopping, removing the tube from the drill press, and clearing the blanks from the tube by pushing them out from the other end.
Rob, always glad for your input...thanks.
Yes, I sharpened the tube...first on the inside, but as you suggested, in my testing, the blanks(9) jammed in the brass tube...firmly!
Then I tried sharpening on the outside...the blanks didn't jam as badly, the test balsa didn't split, but the brass tube didn't cut very well and ran out of steam on the third balsa sheet in the test stack...
so, I cut some teeth in the brass tube and it cut much better.
I still spit one rib trying to feed it on to the tube...partly because the hole was too close to the spar slot and partly because o.d. of my brass tube is a few thou larger than the o.d. of the brass cutting tube.
I'm using carbon tube battens out of old windsurfing sails as the joiner sleeves and the joiner inners and they don't match the brass tube o.d.s .
Gonna flip the plan, set up the right side ribs and drill.
Just caught up on this build thread. It's looking fantastic! Those big beefy wing ribs are a thing of beauty.
Ben
Quote from: bfeist on January 23, 2016, 07:36:20 PM
Just caught up on this build thread. It's looking fantastic! Those big beefy wing ribs are a thing of beauty.
Ben
Thanks Ben...it's supposed to be scale so any applause or boos for appearance belong to the designer...
Measured the root rib, top to bottom and it's almost 3"... you're right...beefy!
I'm going to build the wing in one piece with the carbon tubes in place...I'll decide whether to cut it later...so, I need a bigger build surface...
Went to Home Despot and bought a sheet of 2" pink foam, 2'x8'x2" foam to build the wing on...my table's only 6' and the 7'2" wing hangs over both ends...
Also went to A&J and bought spruce spars and leading edge, cut the ribs for flaps and then test-fitted everything on one side, most on the other...still no glue
Almost ready to start gluing, but before I do, I need some advice from all you aerophysicists and aerodynamic engineer types.
My latest cogitation revolves around dihedral...how much and how to measure it with a semi-symmetrical wing.
My photo shows the recommended diahedral and my measurements at the LE and under the deepest part of the wing.
LE dihedral measures at about 30 mm and measured under the fattest part of the wing is about 52mm...neither meets the plan specified 70mm...
1. Where exactly should I measure to establish dihedral?
2. How important from a stability point of view is hitting the recommended 70mm?
Hi Bill:
Here is an excerpt from Airfield Models which I have always found to be an excellent source of RC info:
"Dihedral is an angle raising the centerline of the wing tip above the centerline of the wing root. Many plans show the dihedral measured from the bottom of the root rib to the bottom of the tip rib. This is incorrect. Dihedral is correctly measured from centerline to centerline."
Here is the link:
http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/dihedral.htm
Andy
I would always measure under the lowest point as compared to the lowest point at the root, resting on the bench. I think your plan is showing at the LE , only as a clear way to show at which rib the height should be measured.
Andy, Rob, thanks for your prompt efforts to enlighten me. I am still confused.
Airfieldmodels is clear about NOT measuring under the deepest part of the wing, but from "centreline to centreline"...sounds simple, but exactly what is meant by centreline??? Root chord to tip chord???
If I understand Rob's answer,
Quote from: piker on January 30, 2016, 09:22:15 PM
I would always measure under the lowest point as compared to the lowest point at the root, resting on the bench. I think your plan is showing at the LE , only as a clear way to show at which rib the height should be measured.
I should measure under the deepest part of the wing....
In the end,it's probably most important I measure the same way the guy who drew the plans did, or...hope Avro's dihedral will work on a 1/8 scale model...
I've included a couple of three views...if they're accurate, my wings are going to look scale, the way they are...but will the model be stable?
OOOHHHH... I missed that...
O.K. Sounds like they want you to draw a straight line front the centre of the LE to the centre of the TE, on both the root rib, or at the rib where the dihedral bend is, to the tip rib that they show as the measuring point. Then figure out the dihedral relationship based on that line. I assume the wing is shimmed up to make those lines parallel to the building board.
The easiest way to do that would be to measure from that line on the root rib, to the building board, then add that measurement to the amount that is to be added at the rib and the result is the amount the centre line of the root rib needs to be from the bench.
Am I right?
Quote from: piker on January 31, 2016, 12:37:50 AM
OOOHHHH... I missed that...
O.K. Sounds like they want you to draw a straight line front the centre of the LE to the centre of the TE, on both the root rib, or at the rib where the dihedral bend is, to the tip rib that they show as the measuring point. Then figure out the dihedral relationship based on that line. I assume the wing is shimmed up to make those lines parallel to the building board.
The easiest way to do that would be to measure from that line on the root rib, to the building board, then add that measurement to the amount that is to be added at the rib and the result is the amount the centre line of the root rib needs to be from the bench.
Am I right?
Rob,
Again thanks for your input. As an inexperienced builder, I am always grateful when experienced builders make time to help those of us who are struggling.
"Am I right?"
Sure seems right to me...the measurements pencilled on the plan in my last photo were all measured from the building board. I measured from the LE as I wasn't sure how washout should be factored in to the measurement if I measured at mid chord...measururing at mid chord will be pretty tough as I've cut lightening holes there in every rib anyway!
Way back in the wing assembly cogitation process I figured that sooner or later I would need lines on each rib from the centre of the LE to the centre of the TE and carefully marked every rib before assembly. These chord lines will help me shim the wing to get both the desired dihedral and washout.
Dihedral
Last night I figured out why the dihedral was off from the plan recommendation. Laying a straight edge along the top of the main spars was revealing...without any glue, the spars were bending under the weight of the wing structure, as my blocking only went to rib 14.
So, blocked the tip ribs to straighten the spars and guess what! Measuring Rob's way, dihedral is now the recommended 70mm!
Washout
I have blocked the wing, so the chord lines on rib 1s are parallel to the building surface. Plan is to block the structure so chord lines on rib 6s are also parallel to the building surface and start the washout from rib 6, increasing to 2 degrees (or something close) at the tip (rib 20). Once everything's blocked and straight...GLUE! :o I'm thinking my trusty white glue as it gives lots of time to move stuff around before it's stuck.