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Old Feb 22, 2012, 10:16 AM
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[QUOTE=Chris Jenkins;20822011]Things are progressing slowly...its the sheer amount of building required for this model that takes the time.

You are not alone! Have been struggling with the underfin section for some while and have just finished at the second attempt. Ianís comment earlier that the thickness was 3/8 and not 3/16 solved one problem. Second problem was adding the sheeting. I had rounded the leading edge of the fin like I thought it should be but then found the sheeting would not follow the curve. Pictures show the finished item.

I plan to use a Laser 70 (on order, promised end of March) and use wedges to give down thrust. In the past I have used wedges from model outlets but find they do not run the full length of the engine mounting lugs. They are smaller and act simply to jack up the rear end and at less angle that stated. Anyone recommend a source for what I am looking for, or suggest a suitable DIY material? Machining metal is out for me. I have tried making my own from hard wood, which was fine except that they soak in oil and soften a bit, allowing the engine after a while to rattle loose.
Ray
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Old Feb 22, 2012, 03:10 PM
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Originally Posted by ol Timer View Post
Anyone recommend a source for what I am looking for, or suggest a suitable DIY material? Machining metal is out for me. I have tried making my own from hard wood, which was fine except that they soak in oil and soften a bit, allowing the engine after a while to rattle loose.
Ray
Paxolin?
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Old Feb 22, 2012, 10:08 PM
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It wouldn't be too hard to file down a couple of wedges - no machining involved.
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Old Feb 22, 2012, 10:12 PM
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[QUOTE=ol Timer;20823560]
Quote:
Originally Posted by Chris Jenkins View Post
Things are progressing slowly...its the sheer amount of building required for this model that takes the time.

You are not alone! Have been struggling with the underfin section for some while and have just finished at the second attempt. Ianís comment earlier that the thickness was 3/8 and not 3/16 solved one problem. Second problem was adding the sheeting. I had rounded the leading edge of the fin like I thought it should be but then found the sheeting would not follow the curve. Pictures show the finished item.

I plan to use a Laser 70 (on order, promised end of March) and use wedges to give down thrust. In the past I have used wedges from model outlets but find they do not run the full length of the engine mounting lugs. They are smaller and act simply to jack up the rear end and at less angle that stated. Anyone recommend a source for what I am looking for, or suggest a suitable DIY material? Machining metal is out for me. I have tried making my own from hard wood, which was fine except that they soak in oil and soften a bit, allowing the engine after a while to rattle loose.
Ray
Hi Ray...Yes....sounds like we are in the same boat !

Ref power...I have a new Laser 70 too for this model, although I'm toying whether my old 62 will do the job (depends on test running, as it hasnt been run for 10 years or more).

Ref the downthrust...I guess the thing to do is to either cut the bearers at the required angle (then the holes will need to be at 90 degrees to the angled face) or angle the bearers down and cut the hardwood thats inside the Fuselarge to allow the tank to sit flat. Haven't got that far yet so I'll watch your solution first

Cheers
Chris

ps: Tail skid/wheel looks really nice. Well done.
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Old Feb 23, 2012, 03:58 AM
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[QUOTE=Chris Jenkins;20830078]
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Originally Posted by ol Timer View Post

Ref power...I have a new Laser 70 too for this model, although I'm toying whether my old 62 will do the job (depends on test running, as it hasnt been run for 10 years or more).
Chris, a .62 should be easily enough. When Neil Tidey started production of the Laser .45, around 1987 or so, he proved the engine by flying it in a Falcon, and the result was an excellent flyer...
Brian
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Old Feb 23, 2012, 04:49 AM
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[QUOTE=brokenenglish;20832020]
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Originally Posted by Chris Jenkins View Post

Chris, a .62 should be easily enough. When Neil Tidey started production of the Laser .45, around 1987 or so, he proved the engine by flying it in a Falcon, and the result was an excellent flyer...
Brian
Yep...I'm sure you are right, Brian.....the 62 would be fine. It was installed in a Majestic Major many moons ago, and for more than 10 years has been in storage and finally liberated last year. Looks okay as I'd liberally coated it with oil internally and externally.

I've got several engines that would be suitable in fact...the Laser 62 and the 70, plus open rocker 60 and as a flyer the Saito 72.. The 62 and the 70 have the same lower block width (35mm) so I'll construct for that and start with one of the lasers and take it from there. At least the 62 is well "run in" if not "run out" !

I want to install the elevator and rudder servos in the tail to simplify field rigging, so it will be a bit of a weight juggling exercise once all the construction is complete and with only the fuselage to cover.

The wings were built and covered more than 10 years ago...so this one is a long build you could say. Hope to get it flying and fettled for Cocklebarrow this year.
I
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Old Feb 23, 2012, 05:31 AM
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10 year anniversary

I was going to suggest to our moderator Scott that maybe we should organise some kind of celebration when Ian's Falcon build thread reaches the 10-year mark!
It also has the merit of easing everyone's conscience... Thanks to the forum, we all now know that we're not the only one who takes years to build a model. I have several 10 or 15 year old half-built models that I'm trying to kick myself into finishing... The real problem is that I'm coming to realise that I think I like building more than flying.
Brian
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Old Feb 23, 2012, 07:05 AM
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I was going to suggest to our moderator Scott that maybe we should organise some kind of celebration when Ian's Falcon build thread reaches the 10-year mark!
It also has the merit of easing everyone's conscience... Thanks to the forum, we all now know that we're not the only one who takes years to build a model. I have several 10 or 15 year old half-built models that I'm trying to kick myself into finishing... The real problem is that I'm coming to realise that I think I like building more than flying.
Brian
The preferring building to flying thing is something that comes with age I think Brian. I still enjoy both equally, but then I'm only 70! Whether it will affect the current generation of RTF flyers once they grow old is another matter!

Nothing to do with Falcons or this thread I am afraid, but as an extension of the above I recall a classic quote from Denis Oglesby, ace aerodynamicist and designer of very individual, sometimes even idiosyncratic, thermal soaring models. He was having some problems with his latest model, and I suggested that, whilst he sorted it out, why not knock a Phoenix or something similar together to use. He fell back in horror and said, "I could never do that, flying someone else's design would be like wearing someone else's underpants!"
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Old Feb 23, 2012, 10:20 AM
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In the engine compartment the pitch of the mounting bolts would not reach the engine bearers so the Laser will be bolted to a 4mm paxolin plate that is recessed in the engine bearers, to minimise height. Underneath, the bearers have been excavated for nylock fixing nuts.
Using 4mm paxolin for wedges I reckon to get 4.5 degrees of downthrust.
Ray
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Old Feb 23, 2012, 11:27 PM
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Oh my goodness it's been 8 years since this all started. It will be done before the 10 years is up though. I need to work on my engine mounting next. I should have done it at an earlier stage but left it till now. The bearers are installed. I just need to work out a few details. I took a break to build a free flight KK Senator which goes together amazingly quick after something like the Falcon.
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Old Feb 24, 2012, 12:57 AM
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Quote:
Originally Posted by ol Timer View Post
In the engine compartment the pitch of the mounting bolts would not reach the engine bearers so the Laser will be bolted to a 4mm paxolin plate that is recessed in the engine bearers, to minimise height. Underneath, the bearers have been excavated for nylock fixing nuts.
Using 4mm paxolin for wedges I reckon to get 4.5 degrees of downthrust.
Ray
He He...that will teach you to install the bearers before settling on the engine choice

Seriously though...for such a large model there is an unexpected lack of space isnt there.
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Old Feb 24, 2012, 12:58 AM
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[quote= "i could never do that, flying someone else's design would be like wearing someone else's underpants!"[/quote]

Love it !
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Old Feb 24, 2012, 03:41 AM
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Quote:
Originally Posted by ol Timer View Post
In the engine compartment the pitch of the mounting bolts would not reach the engine bearers so the Laser will be bolted to a 4mm paxolin plate that is recessed in the engine bearers, to minimise height. Underneath, the bearers have been excavated for nylock fixing nuts.
Using 4mm paxolin for wedges I reckon to get 4.5 degrees of downthrust.
Ray
Ray,
I wonder whether we haven't missed out on an easier solution... It occurs to me that if you'd just used the paxolin, without recessing it, then you would have raised the thrust line by 4mm. which, due to the moment created, must be equivalent to a bit of downthrust, maybe a degree or two, and you could have "fine tuned" with the early flights. Also, Lasers are not "tall" engines, so you wouldn't have the ugliness of an engine way up in the air (too tall). To go a bit further, you could even have inserted a bit of paxolin wedge under your mounting plate. I was thinking about this as, personally, I would have been a bit uneasy about recessing into engine bearers (weakening the bearers and stress points, etc.).
Brian
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Old Feb 24, 2012, 09:33 AM
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Thanks for comments Brian I understand and agree with what you are saying, I am still learning! This Falcon is the third model I have built from plans following on from a Junior 60 and a Majestic Major. If I had had more experience I would not have slavishly followed the original method of joining the wings with a tongue and box and tenons but would have used easier to fit tubing and rods. However, the reason I chose to recess the paxolin plate was because the carburetter is set high up on the Laser and I wish to keep the throttle lever as low as I can.
Ray
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Old Feb 24, 2012, 09:32 PM
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This Falcon is the third model I have built from plans following on from a Junior 60 and a Majestic Major. Ray
Hi Ray....you surprise me...the standard of construction you have achieved is very high, and I admire your bravery at attempting such a project with only two other plan projects before. Very well done indeed.

I've now completed the tail end apart from final sanding and fitment (or otherwise !) of the servos, and the hinges. The fuselage frame and tail will be handcarried back to Wales on Monday for continuation of the build, and matching up with the rest of the airframe. Weight of tailplane minus servos and fin/rudder is 138g/4.75oz.

As a footnote, I wonder how many builders over the years have noticed that as drawn the port side of the tail is 4mm longer than the starboard.
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