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Old Dec 21, 2008, 12:50 PM
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Oops!
Sorry, I forgot to attach the sketch earlier.
I've added it into the previous post now.

Aidan
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Old Dec 21, 2008, 01:16 PM
F3P and Sailplanes-Great!
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S.E. Minnesota
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Thanks

Quote:
Originally Posted by Aio_1
Oops!
Sorry, I forgot to attach the sketch earlier.
I've added it into the previous post now.

Aidan
Very helpful.

Thanks,

Ray
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Old Dec 21, 2008, 04:12 PM
f5b-uk
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When I built my Index I decided to keep the wings in one piece and join the fuselage as shown here with the solid red line. This meant the grain wasn't in the strongest direction for the wings (my sheets are only 700mm wide), but this hasn't been a problem.

Mike
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Old Dec 30, 2008, 12:41 PM
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A couple of construction details

Quote:
Originally Posted by Aio_1
...
I'd suggest avoiding a straight line for the join. If you do something like the green or blue lines in the sketch below rather than the red line it should be stronger and stiffer especially if the edge isn't a perfect match. It might also make it easier to keep the join lined up and straight.

Hope this helps,

Aidan
Aiden,
I did get the Hacker A10-15S for Christmas, so I am building an Index 2.2. I've attached a photo of my progress to date. I have all the foam parts cut out. I cut along the blue line on the plan you provided. The foam as you see it in the photo weighs 50 grams.

I plan to use the photos in posting #95 to guide me in servo and electronics placement. I do have a couple of questions I'd appreciate your help with.

1) I want to try the carbon fiber and shrink tubing control horns shown in the photos on posting #95. I am rather new to building models out of depron, so I can't really tell what size the foam wedges are just by looking at the photos. Can you give me the approximate dimensions of the foam wedges used on the ailerons, rudder and elevator?

2) How much maximum aileron deflection do you suggest I try for in building the plane? This is my first F3P model. Should the ailerons deflect 35 degrees or 45 degrees? I have an Optic 6 transmitter, so I can set up dual rates and use the lower settings until I am comfortable with the model. (if it is helpful, I measured the control rod movement on the servo I plan to use for the ailerons, and find that the control rod moves about 17mm over the full range of movement of the servo control arm.)

Thanks for your help so far. I am really looking forward to flying the Index 2.2. Of course, I'm worried that I'll break it first time out. I expect it will be easier to fly than my current "practice" plane (an Extra330 with a wingspan of 24").

Thanks again for your help.

Ray
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Old Dec 30, 2008, 04:45 PM
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Ray,

Looks good so far! 50g for the depron is about right. I think mine was about 50g with the depron assembled and the bracing carbon added. If I'm remembering that correctly the difference is probably due to small differences in the depron density. The bracing carbon doesn't add much and so long as you're sparing with the adhesive you'll still be on target for a good finished weight.

The size of the wedges does as you've realised depend on the servos and the arms you've got fitted to them. The surface deflections you end up using will also depend to a certain extent on your own preferences. If you like a fairly lively plane I think you should aim to have 45 or 50 degrees available on all surfaces. You may decide you don't need this much and if that's the case just reduce the servo travel from the transmitter.
My Dad likes his with about 30 degrees on the ailerons, 40 on the elevator and rudder. I like about 50 degrees all around for fun flying but I prefer a tamer setup for smooth precision flying. I think 40 all around and a reasonable amount of expo is a good starting point.

It is best to use as much of the full servo travel as possible to reach the biggest deflection you'll need. That allows you take advantage of the maximum torque and resolution available. In practice it's not all that critical for most of us. In later planes if you know you only want 40 degrees on the ailerons you can make higher wedges but it's better to have too much than too little travel. If your servos rotate 45 degrees each way at 100% travel then make the distance from the hinge to the pushrod connection the same as the distance from the centre of the servo to the other pushrod connection and you won't go far wrong.

I look forward to seeing how you get on. Do let me know if you've any other queries or if my answers aren't clear - I'm sometimes guilty of that!

Aidan
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Old Dec 30, 2008, 05:02 PM
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Makes sense

Quote:
Originally Posted by Aio_1
Ray,

.... If your servos rotate 45 degrees each way at 100% travel then make the distance from the hinge to the pushrod connection the same as the distance from the centre of the servo to the other pushrod connection and you won't go far wrong....



Aidan
Aidan,
Thanks for getting back to me so quickly. What you said does make sense. I did, however, have to read the above sentences a couple of times before I understood them. One of the things I enjoy about this hobby is learning new things.

I'll start assembling the pieces of my Index 2.2 tomorrow. Tonight I get to go to a local gym and fly my Extra 330 with the 24" wingspan and my Mini IFO!

Thanks again.

Ray
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Old Jan 02, 2009, 11:11 AM
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Making progress

Here are a couple of photos of my progress to date building the Index 2.2. The foam parts of the plane weighed 50 grams. Assembled with the hinges and carbon fiber bracing in place, the plane weighs 57 grams.

This is a much larger plane than I imagined it would be. I am beginning to wish I had larger servos. I plan to use servos that I already have. I plan to use my Blue Arrow BA-TS-4.3 (10 oz. in. torque) for the ailerons and my Blue Arrow BA-TS-3.6 (6.9 oz. in. torque) servos for the rudder and elevator. I hope they will be strong enough to at least get me started in flying F3P style with the plane. I think I'll start saving up to get a set of the Dymond D47 servos I read about on many of the postings.

Ray
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Old Jan 05, 2009, 06:11 PM
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I notice on the plan it mentions the depron laminations on the leading edge produce different effects if left square or rounded of.

What are the different effects they produce? Anyone any experience of this?

Thanks
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Old Jan 09, 2009, 01:49 PM
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Going to try plywood control horns

I wanted to try the depron/carbon control horns shown in posting #95 as I build my Index 2.2. However, I don't have small enough shrink tubing to shrink tightly around the 1mm carbon fiber push rods. I think I'll go with home-made plywood control horns.

Here are a couple of photos of the control horns I made this morning. I used 1/32" aircraft plywood from the LHS. The notch at the back of the control horn should help insure that it is securely attached to the control surface.

I calculated the distance from the control surface to the hole for the control rod connector using information provided by Aidan a few posts up. In this case, the distance from the center of my servo control horn to its outermost hole is about 12mm. I put the hole in the plywood control horns 12mm from the surface of the control surface.

Ray
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Last edited by RayPB; Jan 09, 2009 at 01:53 PM. Reason: Corrected spelling error
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Old Jan 10, 2009, 10:33 AM
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Ready for maiden flight

I finished my Index 2.2 last night and hope to maiden it at the field house at a local college next Tuesday evening. Since this is my first F3P plane and only my second 4-channel plane, I haven't spent a lot of effort making it pretty. I just painted the cockpit to help with orientation as it flies.

Weight without battery: 116 grams
Weight with battery: 137 grams
Battery: Polyquest 300 mAh 20C
Motor: Hacker A10-15S
Prop: GWS 7x3.5 DD
ESC: CC Thunderbird 9
Receiver: Corona 4-channel

I'm a little concerned with the flexibility of the 1mm carbon fiber push rods. I'll see how it goes. I may either add more guides or change to 1.5mm rods.

I am very anxious to see how it flies.

Ray
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Last edited by RayPB; Jan 10, 2009 at 10:36 AM. Reason: Corrected typo
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Old Jan 10, 2009, 10:48 AM
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RayPB

I use 4 guides per pushrod on my pattern planes. If you think it's too flexible, then it probably is. It looks like the rudder should work fine, but only two on the elevator would be more of a concern.

Mini Ifo
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Old Jan 10, 2009, 11:37 AM
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Quote:
Originally Posted by mini ifo
RayPB

I use 4 guides per pushrod on my pattern planes. If you think it's too flexible, then it probably is. It looks like the rudder should work fine, but only two on the elevator would be more of a concern.

Mini Ifo
Thanks for the input. I'll add more guides on the elevator side before the maiden flight.

Ray
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Old Jan 10, 2009, 07:30 PM
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Wing area on Index 2.2?

Has anyone calculated the wing area on the Index 2.2?

Ray
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Old Jan 11, 2009, 11:46 AM
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That's looking great Ray.
Good work on the weight too. 136g is excellent for your first F3P plane and it should fly nicely at that weight.
The 1mm pushrods should be fine. That's what I use on most of my planes - typically with only 2 supports and there's no noticeable flex. It might depend a little on the quality of the carbon rod. I've heard some producers skimp a little on carbon and use extra resin (which would make it more flexible). I don't know if that's true or not.
If you put a little bit of pressure on the control surfaces does the rod bend at all? I just checked and mine doesn't.
If you do have a problem I'd suggest adding supports instead of switching to 1.5mm which would add a few grams.

Best of luck with the maiden flight!
I hope you like it.

Aidan

P.S. Those wheels look good. Where'd you get them?
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Old Jan 11, 2009, 11:59 AM
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Quote:
Originally Posted by RayPB
Has anyone calculated the wing area on the Index 2.2?

Ray
The wing area is shown on the plan: 14.7sqdm
That's 228sqin.

I just realised that I listed it as "Area" not "Wing Area" so it's a bit vague.
The measurement given is for the wing outline extended all the way to the centreline which is the convention for aircraft specs (full size and model).
I've noticed that some "shocky style" designs include the entire horizontal area in the wing area calculation. If the Index figures seem a lot smaller than some others this will probably be the explanation.

Aidan
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