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Chapter One - RCM&E's build-a-plane series


Nigel Hawes
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Posted by jeff2wings on 05/11/2015 18:29:08:

Would it not be better to build the fuse for the symmetrical wing and then add a bit extra onto the 3ch wing under side ? just a thought .

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or build the new aileron wing with flat bottomed wing ribs in the center to sit on the 3 channel fuz?...just a thought..

ken anderson...ne....1 flat bottom dept.

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The ability to swop between the 2 wings seems a nice idea but the practical aspect is you not only need to change the wing seating but ensure the CG is still correct ( aileron wing could be heavier at TE?) and in any case you need to swop the rudder into a different Rx socket. Then the pilot needs to remember that whilst taxying that the rudder is now on the left stick instead of the right. So as it's somewhat confusing to a novice pilot it probably won't be a regular occurrance but a once only job.

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  • 3 weeks later...

Hi all,

I am completely new to building planes from plans and I am wondering how exact I need to cut the ribs.

I started building the aileron wing by making a ply template of the rib and using this template to cut the balsa ribs. The result is as in the pictures. Is this acurate enough? I know, I need to sand all ribs flush but do I need to sand to much?

ribs1.jpg

ribs2.jpg

Any advice is appreciated.

Regards, Jeroen.

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Welcome to the forum Jeroen....

The more accurate the parts are cut the easier the build & the better the plane will fly. For ribs the main thing is to have them all the same length & to have the spar slots accurately cut. Any errors here will mean that the ribs will not fit tightly into the rib structure leading to weaker joints.

Looking at your pics then for sure sand the ends so each rib is the same length & then ensure you cut the spar slots accurately so it all lines up with the plan.

The D box wing on the Chapter One is very strong so a few..er..discrepancies won't weaken it unduly but do try & keep it as accurate as possible.

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Welcome to the forum Jeroen

As the others have said the accuracy is fairly important, I strive to be as accurate as I can even on bits that perhaps don't warrant it as it becomes a habit, one thing that you probably already know but I will say it anyway, don't try and cut things to size, sand to size its much esier to control the accuracy Just cut slightly oversize then sand to the line or template

Cheers

Danny

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Posted by Mowerman on 24/11/2015 22:58:22:

Make it easier by making 2 ply templates then clamp the stack of ribs between the templates and sand to the templates and cut the spar slots.

Mowerman makes a good point.....a good example of the technique in this thread

The RM Trainer is pretty similar to the Chapter One.

@Tone Mak.....I don't know what the situation is re a laser cut set for the Aileron wing...I have asked the question of "those who know" & will advise....

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  • 5 months later...

The aileron wing states to use 4 mm spruce spars. I see on this thread that another builder was having trouble sourcing 4 mm spruce, but there was no update or reply to this. I'm about to commence this build and I find the same problem. What have others used? My local model shop had 1/8 spruce; would this be sufficient?

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I would use hard balsa spars with good medium grain spar webs. It's not a hardcore model, and i'm pretty sure it will do fine like this. I build aerobatic models designed by peter miller using this method which is also advised on his plans and never had any problems. Even with good abuse of aerobatics.
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Thanks Daniel,

I'm still learning to fly at present, so I need my wings to be as tough as possible. I used hard balsa in the Jocasta that I built, but the wing broke in a hard landing (read crash). The second wing with spruce spars has fared better. As the there is only 0.8 mm difference between 4 mm and 1/8 I'm wondering if it will be sufficient. If you think hard balsa would be more than adequate then I'm reasoning that 3.175 mm (1/8) spruce ought to be too.

I tried sending a PM to Nigel, but for some reason this site isn't working properly (at least not on my iPad) and many of the links are not responding.

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Well I think yes 1/8th spruce would do fine too, I dont remember the plan well but if it says to use bolts instead of rubber for the wing attachment, I would prefer, rubber bands for the beginner in an event that you give a knock on the wing during a landing. If bolts, dont use hard ones or they wont shear easily if a mishap occurs. You can use 5mm hard balsa for the spars aswell if you wish and make the first row of ribs with double spar webs if you are concerned for rigidity.
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  • 4 weeks later...

At last I've begun to build Chapter One with the aileron wings. The first thing I noticed, using the plan from the magazine, is that the fuselage is actually 1/4" bigger than a sheet of 36" balsa! Of course 1/4" isn't going to make that much difference, but once I'd cut out the sides I added it anyway.

F1 is drawn on the plan as being 2 3/4"; measuring on the side elevation, it should be 2 3/8". I bored a hole in this to take the motor leads and a small cutout below where the motor will be to allow cooling of the esq. as I'm using the motor out of my ill fated Wot4 I had to modify its mount to fit (in its original form it's too long and too wide). I'm also using the Wot4's U/C, which is a bit taller and wider; I don't think wider will be a problem and being taller will simply increase the angle of attack at take off. The Wot4 will also be donating it's servos and snakes. I was hoping to use the tail wheel too, but haven't figured out a way to make it fit

I cut and shaped the dihedral braces as per the plan and glued them in; however, matching up the second half of the wing I found the dihedral to be way over the 1/2" specified, so I had to carefully cut them out and start again. Incidentally, the root ribs are shown cut into three sections; for the position shown on the plan for the dihedral braces, the cut positions for these ribs is drawn wrong. As I couldn't find any 4 mm spruce, I used 1/8" sq for the rear one and 5/32" X 1/8" for the two central ones. I also slightly increased the width of the trailing edge by 1/16" and recessed the rear of the ribs into it. I figure that this ought to strengthen the wing in lue of the slightly undersized spruce spars.

Other than the above, the build is progressing well. I've yet to cut the modified wing seat into the fuselage. I had thought to use a rib template and do this in advance, but the instructions say it'll be more accurate if I do it when the wing is finished. I've never done it this way before, so I hope I can get it right. I don't have one of those tools for checking wing incidence and don't know what it ought to be anyway. Presumably 0 degrees for wing and tailplane?

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Not really. You still need primary roll or yaw control on the right stick (mode two). You can't "reserve" controls and hands.
You could of course build ailerons and fix them, but I'm guessing the aileron wing has less dihedral.

I'm late to the thread but it looks like a cross between a High Boy and a Tauri. (Or Taurus, I learnt in one of them anyway )

David
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Posted by David perry 1 on 25/06/2016 12:09:53:
Not really. You still need primary roll or yaw control on the right stick (mode two). You can't "reserve" controls and hands.
You could of course build ailerons and fix them, but I'm guessing the aileron wing has less dihedral.

David

Hi David,

Sorry, I don't understand your reply in relation to my post above. Could you explain? 😊

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Yes, the idea of fitting but freezing ailerons. I was just saying dont fit and freeze them and try to fly rudder on your left hand. Fit and freeze ailerons and fly rudder control by all means, but fly rudder on the right stick. Primary steering must always be on your primary steering hand...you cant reserve a hand. Well, you CAN, but itd be odd later

D

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