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Old Oct 18, 2011, 02:07 AM
Heli's and gliders, what else?
BarnOwl's Avatar
Nederland, GE, Slijk-Ewijk
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Originally Posted by delperena View Post
I am doing the same inside plywood firewall. Unfortunately, 20 minute epoxy BSI (Bob Smith Industries) and JB Weld did not work for me. I searched this thread and found your plywood/epoxy application.

Could you please share how you managed to stick plywood to the fuse.

Thanks,

Del
I used 5 min epoxy to weld the plywood firewall by pooring it in the fuselage and then sticking the plywood on top.

In this thread there are pictures. So far it's been holding nicely.
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Old Oct 18, 2011, 03:26 AM
Reap the wild wind
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Bristol,UK
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Originally Posted by skyhawk newbie View Post
Isn't this the guy that got the FPV law's changed . .After his stunt in NewYork..
I don't know about that but I know the UK BMFA rules are strict about FPV flying. You have to fly with a buddy box pal who maintains visual with the model at all times. And I don't think a telescope would count
Anyway, glad you all enjoyed the vid. Just shows, I spend waaaaay too much time surfing the web
Andy
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Old Oct 18, 2011, 05:38 AM
Not a newbie anymore..
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Ireland, Cork
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Originally Posted by headlessagain View Post
I don't know about that but I know the UK BMFA rules are strict about FPV flying. You have to fly with a buddy box pal who maintains visual with the model at all times. And I don't think a telescope would count
Anyway, glad you all enjoyed the vid. Just shows, I spend waaaaay too much time surfing the web
Andy
As far as I know , there's no rules in Ireland...
I haven't seen anything on the M.A.C.I web site about flying FPV..

Sean
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Old Oct 18, 2011, 07:01 AM
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Canada, ON, Oakville
Joined May 2008
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Quote:
Originally Posted by delperena View Post
I am in search of methods to attatching to the fuselage, specifically, a plywood firewall to the inside of the fuse nose. (Please refer tom above post).

Your method seems interesting. I am just curious how structural integrity is enhanced if it is not firmly attached to the fuselage, especially along the inside periphery of the nose.
I didn't bother with glue, the motor screws and extra plywood washer / firewall works fine for me.
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Old Oct 18, 2011, 02:33 PM
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Originally Posted by Toppers View Post
I didn't bother with glue, the motor screws and extra plywood washer / firewall works fine for me.
I agree. I did the same thing and I'm sure it's enough.
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Old Oct 18, 2011, 03:44 PM
Not a newbie anymore..
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Originally Posted by Toppers View Post
I didn't bother with glue, the motor screws and extra plywood washer / firewall works fine for me.
As most of you know , I fiberglassed the nose/firewall of my Phoenix...

I think That Toppers way would work fine..it has for him..
But I would of CA Glued the 2 plywood pieces together, then screwed them secure from the out side of the fuse... one screw on each side ,just infront of the vents...



Sean
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Old Oct 18, 2011, 11:31 PM
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Thanks for Your Response

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Originally Posted by Toppers View Post
I didn't bother with glue, the motor screws and extra plywood washer / firewall works fine for me.
In an ideal rc glider world, where landings and aerobatic maneuvers are smooth and of insignificant stress to the airframe, then a Stock Phoenix 2000 should survive.

However, my real world is far from ideal.

Ten days ago, I received my Phoenix 2000 (HK USA). As most, I recognized the weak points, among those is the motor mount. No big deal, I thought, with a circular 1/8" plywood epoxied to the inside of the nose should do it. But epoxy did not work for nor JB Weld.

To BarnOwl, thanks for "EpoxyFlooding" idea, although I am somewhat skeptical that epoxy really bonded to the plastic fuselage. I did a mallet test.

A plywood that is not bonded to the inside of the fuselage, to me, does not serve any structural support. I don't think it can be considered a firewall (consult a structural engineer to confirm. No, I am not one). It is but a spacer.

My research led me to Devcon Methacrylate (Plastic Welder). I just purchased some from Amazon. I will gladly report if it works.

If, Devcon does not work me, I will follow "skyhawk newbie's" approach - the best option I can see.

Del
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Old Oct 19, 2011, 07:33 AM
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Not sure why anyone would take a mallet to a new glider to test it's structural integrity.... that's a bit like taking a new car and finding a wall or tractor-trailer to hit?

Planes and especially gliders need to be light, and so I would recommend keeping your reinforcements to a minimum.

In my limited experience I find hot glue and gorrilla glue bond best to plastic... but I have only tried the mainstream glues (CA, weldbond, epoxy, canopy glue, wood glue, gorrilla glue, hot glue).


Toppers
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Old Oct 19, 2011, 07:44 AM
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Oh I forgot... talking of ideal RC glider worlds... my third flight on my first day flying the Pheonix... I was trying flaps and slowed the glider to a stop about 15'-20' above the ground. It dropped it's nose and nose-planted HARD.... my firewall / spacer / motor mount was absolutely fine... the fuselage just aft of the nose was completely buckled and crumpled and now angled 20` down as well..... I was crushed too !!! But the beauty of the polyethene fuselage is I just pulled the nose forward and up and the crumple just popped back to the stock shape... no harm done. I was cautious of the nose strength for a flight or two... but many dozens of flights later had forgotten the incident altogether until you mentioned 'ideal world'...

Better to have a lighter more flyable plane / glider and fix the odd repair than reinforce it to death... that's why I fly foam planes... I've got pretty good repairing with epoxy and gorrilla glue.

I just remembered... that same nose-in crash cracked a wing in half too (epoxied back as new...no problem).

.....none of us live in a ideal RC world.

Toppers
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Old Oct 19, 2011, 08:21 AM
Heli's and gliders, what else?
BarnOwl's Avatar
Nederland, GE, Slijk-Ewijk
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Originally Posted by delperena View Post

To BarnOwl, thanks for "EpoxyFlooding" idea, although I am somewhat skeptical that epoxy really bonded to the plastic fuselage. I did a mallet test.

A plywood that is not bonded to the inside of the fuselage, to me, does not serve any structural support. I don't think it can be considered a firewall (consult a structural engineer to confirm. No, I am not one). It is but a spacer.
Well, there's some people here that even re-inforced the outside with fibreglass and epoxy. There's even a bloke that used an aluminium firewall without bonding.

Probably if I hit my nose cone hard enough the thing will come apart. The point is it is working: It gives me the extra structural integrity I need for the firewall. Even if it should come loose it is stil giving that extra strength so I am not worried about it at all.....
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Old Oct 19, 2011, 09:24 AM
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Originally Posted by Toppers View Post
Not sure why anyone would take a mallet to a new glider to test it's structural integrity.... that's a bit like taking a new car and finding a wall or tractor-trailer to hit?

Planes and especially gliders need to be light, and so I would recommend keeping your reinforcements to a minimum.

In my limited experience I find hot glue and gorrilla glue bond best to plastic... but I have only tried the mainstream glues (CA, weldbond, epoxy, canopy glue, wood glue, gorrilla glue, hot glue).


Toppers
Gentlemen, I am looking for sensible solutions. I would suggest consulting experts, e. g., structural engineers. Regretfully, I find yours unacceptable.

Yes, gliders should be light! Then why add something that does not serve a purpose but provide a false sense of security.

Most say it (spacer modification) works. I am sure many would also say it works stock.
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Old Oct 19, 2011, 09:39 AM
Heli's and gliders, what else?
BarnOwl's Avatar
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..........
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Old Oct 19, 2011, 09:47 AM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
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Quote:
Originally Posted by delperena View Post
Gentlemen, I am looking for sensible solutions. I would suggest consulting experts, e. g., structural engineers. Regretfully, I find yours unacceptable.

Yes, gliders should be light! Then why add something that does not serve a purpose but provide a false sense of security.

Most say it (spacer modification) works. I am sure many would also say it works stock.
What do you mean by sensible soltion...

Theres ove 900 postes on this thread from Guy's that have
been flying /crashing / Moding the Phoenix to there needs ...

Re-read this WHOLE thread for a sensible soltion...
Then go and see a structural engineer who fly's the phoenix 2000 glider......

what do you want for a $75 PnP Glider .... BLOOD....


..
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Old Oct 19, 2011, 03:48 PM
CURIOSITY Has Landed!
Fugitive_Bill's Avatar
Sydney, Australia
Joined Jul 2005
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Quote:
Originally Posted by delperena View Post
Gentlemen, I am looking for sensible solutions. I would suggest consulting experts, e. g., structural engineers. Regretfully, I find yours unacceptable.

Yes, gliders should be light! Then why add something that does not serve a purpose but provide a false sense of security.

Most say it (spacer modification) works. I am sure many would also say it works stock.
When ya get back from consulting your Experts, Structural Engineers and Rocket Scientists, let us all know what the true solution to the infamous Phoenix 2000 motor mounting/strengthening problem is.

Be sure they don't forget to strap it to a rocket sled and run it into the side of mountain - it's the only way to be sure!

B!LL!
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Old Oct 19, 2011, 06:36 PM
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Australia, New South Wales, Sydney
Joined Jan 2011
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Quote:
Originally Posted by delperena View Post
A plywood that is not bonded to the inside of the fuselage, to me, does not serve any structural support. I don't think it can be considered a firewall (consult a structural engineer to confirm. No, I am not one). It is but a spacer.
It is not "but a spacer" if its diameter is any greater than that of the motor. It doesn't take a structural engineer to understand the logic.

If the contact patch between the motor and the surface in front of it is say effectively 25mm in diameter, the body of that motor rigidly prevents flexing of the firewall within the 25mm circle.

Now add a plywood/aluminium/stone disc in front of the motor, say 30mm in diameter. It's held by screws just as tightly as the motor, even without a glue bond, and therefore it resists flexing of the plastic firewall in a backward direction. If the corresponding disc at the front of the firewall is also sufficiently wide and inflexible, then there'll be no flexing in that direction either. In the case of the Phoenix that's the ~40mm steel plate into which the stock motor screws are counter-sunk.

Make the rear plate even wider, 35mm or 40mm, and there's correspondingly less flex again. The effect is achieved without glue, and it clearly means the disc touching the motor is more than a "spacer" on account of its bigger diameter.
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