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Old Aug 03, 2010, 04:49 AM
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United Kingdom, Wrexham
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Interesting question marhar, I am in the process of assembling mine now using a 2" monoblock. My only concern is a good way to align both sides of the fuselage, to get it all square. This is my first non profile build so lacking a little confidence. Any tips would be a blessing for me also.

Cheers

Ash
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Old Aug 03, 2010, 05:58 AM
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Ontario, Canada
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Originally Posted by plane_spotter View Post
Interesting question marhar, I am in the process of assembling mine now using a 2" monoblock. My only concern is a good way to align both sides of the fuselage, to get it all square.
Normally, here is the process I use:

Materials:

- Gorilla Glue White/Fast Drying
- White glue, Beacon's Hold The Foam
- Small 90 deg square (6-8")
- A 3"x 8" scrap of foam to simulate the elevator

1) Glue the monoblock to one of the fuse sides and let the glue set up. (normally 15min for Gorilla Glue White/Fast Drying)

2) Dry fit the other fuse half to ensure it fits well. Then lay the fuse on a flat table.

3) Apply glue and attach the other fuse side.

4) Install the scrap piece of foam in the H. stab slot/location. DO NOT glue.

5) Using a square, check the following:

- The temporary H. stab is perpendicular to the table
- The wing saddle is perpendicular (both sides of the fuse touch the square) at both the front and back.
- Weigh down with suitable weights until the glue dries.

If you get it right, the fuse should come out very straight and true.

You can then glue the upper & lower fuse portions checking alignment as you go. I normally use white glue for this. Let dry, then remove temp H. stab, install the proper piece. The fuse should stand true on the table so it's a simple matter of making sure H. stab is level.

Last piece is the vertical fin. Use your square and masking tape to check and maintain alignment until the glue sets.

If you do get a bit of misalignment in the end, it's not a deal breaker. The plane will still fly.
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Old Aug 03, 2010, 06:37 AM
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insomaniac45's Avatar
UK, Eastleigh, Eastleigh
Joined Jul 2010
546 Posts
thanks jack.

it has still left me a little confused.
my current battery, is an 850mah 2s 15c, but i need something that would give me around a 15min flight time.

would it haul a 2000mah,
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Old Aug 03, 2010, 07:29 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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Originally Posted by insomaniac45 View Post
thanks jack.

it has still left me a little confused.
my current battery, is an 850mah 2s 15c, but i need something that would give me around a 15min flight time.

would it haul a 2000mah,
You mentioned a weight of 16 oz., a typical 2200 mAh LiPO pack would weight about 175 grams/6.25 oz. If the battery weight was not included in your 16 oz. estimate it bring the weight up to 22 oz. or 1-1/4 lbs or so. Again looking at the 90 Watts per pound figure it would call for 113 Watts or so of power to fly that nicely. So you should still be OK.

That power need estimate is on the conservative side, and not an absolute must:

Approximate power requirements:

50-70 watts per pound; Minimum level of power for decent performance, park flyer/slow flyer models
70-90 watts per pound; Trainers and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models

Those figures date back to NiMH batteries and brushed motors, you can easily reduce those figures by 40% or so for the much more efficient LiPO batteries and typical brushless motors we are using now
.
In most cases you'll find that those power levels will give you more than adequate power for short takeoffs with good control and find that you can throttle back and will only need a fraction of the power to sustain flight.

To estimate the duration you need to know the current drawn and battery size in mAh. The math is simple enough. Typical battery efficiency would be that you can use 80% of a battery's rated capacity. So a 2200 mAh battery would give you 1760 mAh (2200 x .80) of useable capacity.

1760 mAh = 1.76A
1.76A x 60 minutes = 106 Amp/Minutes of duration
106 Amp/Minutes / 12A = about 9 minutes (106 / 12) the motor's continuous current rating.

And I would not be surprised at all to find that you can fly at half throttle or 6A and that will get you up into the 18 minutes of so range for duration.

Another way to estimate the performance would be to see some prop testing data for the motor with the prop you intend to use and see how much current your prop draws and how much thrust it produces. Slough RC does not have any prop testing data there but if you look at a motor of similar weight and Kv value, with a 3S battery, and your prop, it will give you a feel for the thrust you can expect to see.

You'd like to see a system that produces a thrust that is, at a minimum, about 80% of your planes weight. If it produces 100% (22 oz.) the plane will have very good performance and 125% or so would be enough to make it a very high performance trainer for sure.

Here is a motor of similar weight and Kv that produces about 30 oz. of thrust with a GWS 9050 prop on a 3S battery:

http://www.headsuprc.com/servlet/the...0-Sport/Detail

That would be about 130% or so of your plane's 22 oz. weight with the 2200 mAh battery and, again, it all points to there being more than adequate power in the power system.

Jack
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Old Aug 03, 2010, 09:05 AM
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LaGrange, GA
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Originally Posted by philipa_240sx View Post
The best method I have found is water based acrylic craft paint (ie. Apple Barrel brand from Wal-Mart.) sprayed with an air brush. I dilute mine 2:1 with rubbing alcohol (water will work too) and run it through a fine mesh strainer before using.
I'm with Philip on the Apple Barrel and equivalent paints. They work pretty well as he describes them. I've got a Badger airbrush, but it's the same type of cheapie single action airbrush that you get at HF or Walmart. If you paint something and set it in front of a low-speed fan, it's dry in 10-15 minutes and you can recoat, continue with your build or whatever.

Hey Philip, how did you make those cowls? Did you vacuum form a soda bottle or something? You have a link to a thread somewhere that describes how to do that?
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Old Aug 03, 2010, 09:12 AM
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LaGrange, GA
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Originally Posted by plane_spotter View Post
My only concern is a good way to align both sides of the fuselage, to get it all square.
That's kind of what the monobloc does.... if it's cut out right to the plan and you glue the sides onto it straight, it lines up the plane for you. Then all you have to do once that dries is when you bring the fuse sections together at the rear, eyeball them to make sure the fuse comes straight back and is not shifted to one side or the other. It's actually easier to do than explain. The monobloc makes for a nice, straight build. Go for it!
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Old Aug 03, 2010, 09:16 AM
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LaGrange, GA
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Originally Posted by philipa_240sx View Post
5) Using a square, check the following:

- The temporary H. stab is perpendicular to the table
- The wing saddle is perpendicular (both sides of the fuse touch the square) at both the front and back.
- Weigh down with suitable weights until the glue dries.

If you get it right, the fuse should come out very straight and true.
I agree with you...... HOWEVER! LOL It must be my carpentry skills.... every time I pull out my square and try to hold, glue & measure, my planes end up crooked as can be. When I just use the TLAR method, they come out great every time.

Quote:
Originally Posted by philipa_240sx View Post
If you do get a bit of misalignment in the end, it's not a deal breaker. The plane will still fly.
Lucky for me, this is true also! LOL
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Old Aug 03, 2010, 09:18 AM
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LaGrange, GA
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Originally Posted by insomaniac45 View Post
would it haul a 2000mah,
Oh yeah.... I've got a 2S 2400mah Zippy battery that's about 6 inches long.... My 42 hauls that with no problem at all. I've got a 3S 1550mah that is probably heavier than the other one and it doesn't complain about that one either.
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Old Aug 03, 2010, 11:20 AM
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Wilfor's Avatar
Canada, BC, Williams Lake
Joined Jan 2010
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Once your sides are glued to the mono block . Setting it on a piece of grid paper when gluing the tail together works well to make sure the tail is aligned .
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Old Aug 03, 2010, 03:30 PM
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Joined Jan 2008
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I usually clamp a block of wood to the edge of the table/counter that is at least a bit taller then the width of the fuse. I then place one side of the fuse on the table with the wing seat against the long edge of the block and the small tab at the front of the seat against the end of the block. Glue up the mono block on both sides and then locate it on the first side. A few pins through the block and into the side will help keep the parts from sliding around. Next place the second side on top and pin up through the mono block as you did with the first side. Verify that the parts are against the wood block and clamp the parts with heavy objects of you choice. Set something heavy on the table to hold the fuse against your wood block so all of the parts stay in alignment until dry.

This method results in well aligned fuse parts and a perfectly flat and square wing seat. Of coarse this method requires that your fuse parts are cut pretty much the same and a flat wing seat. Also I generally cut the slot for the h-stab after the fuse is all together to assure that it is parallel to the wing seat. Works out pretty good.

Rob...
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Old Aug 03, 2010, 05:25 PM
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Ontario, Canada
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Originally Posted by JohnsPop View Post
Hey Philip, how did you make those cowls? Did you vacuum form a soda bottle or something? You have a link to a thread somewhere that describes how to do that?
Yup, read here starting at post #19:

http://www.rcgroups.com/forums/showt...0&page=2&pp=15

Soda bottles are blow molded using PET plastic. When reheated with a hot air gun, the plastic will shrink almost back to it's original shape. It's a cheap way to form cowls, canopies, etc. Just about any rounded shape.

Painting is a snap. Rough it up with some fine grit sandpaper and paint with the same water based acrylics as the rest of the plane. The paint sticks well and it takes quite a beating.

If you are like me, you will soon be hoarding pop bottles from the recycling!
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Old Aug 03, 2010, 05:29 PM
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Originally Posted by mxspode View Post
I usually clamp a block of wood to the edge of the table/counter that is at least a bit taller then the width of the fuse.
I like that method! Simple to use with materials at hand. Nice job!
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Old Aug 03, 2010, 11:45 PM
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Canada, BC, Williams Lake
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Well i learned a couple things this weekend

1: Never cover your BB with a towel to keep in dry when on a party boat in the middle of a lake , turns out drunk people think it looks like a pile of towels and will step on it
2: Always bring a second plane , which i did
3: Make sure when your showing off you do it with some altitude , Which i didn't again

1 broken bird and 1 wet one what a fun weekend

Oh but there all glued up and will be ready in the am
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Old Aug 04, 2010, 09:57 AM
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LaGrange, GA
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Originally Posted by philipa_240sx View Post
If you are like me, you will soon be hoarding pop bottles from the recycling!
Why not? Between model railroading, foamies and SPADs, I hoard pretty much everything else! LOL Thanks for that link.
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Old Aug 04, 2010, 12:53 PM
Not always grumpy!!
insomaniac45's Avatar
UK, Eastleigh, Eastleigh
Joined Jul 2010
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Cheers guys,

well im off to my local hobby shop tomorrow, to see if their prices are any good.

if so i will be purchasing a set of nice new batterys,

then next week another charger. the one i got takes forever. (it came with my helicopter, on my 850mah it takes about 2 hours to charge from dead )

have not been able to get my bb up since the maiden. weather has been too bad. but as soon as i send her up again, i will try and get a vid for you guys

also. is there any type of paint you guys use, that will not attack the foam, but will cover the reinforcing tape well?

thanks every one. with out your help and advice. i would have given up along time ago
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