Colin Anderson
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Posts posted by Colin Anderson
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I've just seen that the image I posted in my previous post doesn't show (at least not on an iPad). Sorry about that guys.
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New (second wing) completed. All that remains is to add the glass fibre reinforcement and cover. Wing tips are salvaged from the first (crashed) wing, as are the ailerons. Note reduced dihedral.
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Hi Glyn,
Yes, I covered my slotted servo plates without the servos in place. As the plates are quite thin it's just possible to get the pointed end into the slot and secure the edges; that's what I did. When it came to covering the wing I did so without the servo plates in situ, in order to the covering around the edges of the hole. Once the servo plate is screwed back in place this provides this provides a nice neat solution.
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Your welcome, Glyn. I've had lots of help on here. I'm only too glad that I can help someone else in a small way. Best of luck with your wing. Mine's nearly completed. I think I've made a better job of this one than the first one! Practice makes perfect! I've made this one with slightly less dihedral; it took me ages to work out the dihedral braces and the root rib angle! 😊
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Hi Glyn,
It's good that you've only built the one side! When you do your second side, lay out the lower sheeting and all capping strips, before adding your spars and ribs - you won't need packing.
How to remedy the half you've already built: the outboard half of the wing shouldn't be a problem. You'll just need a capping strip to run along the length of the aileron hinge support; spanning R2, R3, R3, R4 and R2. I would think that, if you're very careful, you could probably cut the five ribs (the two inboard ribs have sheeting beneath them?) out of their slots in the trailing edge, fit the cap strips and reglue. That's how I'd do it.
We all make mistakes. I'm in the process of making a new wing, following a crash. Yesterday, when I came to fit the leading edges I found that I'd cut them to the same length as the trailing edges! As they say, measure thrice, cut once! 😊
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Hi Glyn,
I've no idea who John is, but never mind. 😊
Okay, cap strips. The top cap strips shouldn't be a problem; I presume you've got a step behind the leading edge sheeting and one at the other end, where the rib meets the trailing edge. However, what about the lower cap strips? Again, I guess you'll have a step behind the lower leading edge sheeting. But, as you've put the ribs in without the cap strips, have you got a step where the underside of the ribs meet the trailing edge? From your image it's clear that you have no cap strips at all.
Regarding your images. Usually posted images will upload in the orientation that they are saved in. If you rotate an image within a program and upload it from that program it will still upload in the original format; unless of course you're using a program like Lightroom which can upload directly.
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Hi Glyn,
Have you put the cap strips on all the ribs, top and bottom? Also, by inboard of the wing, do you mean the root, where the two halves join the centre section? If so, then the sheeting extends back to the trailing edge (top and bottom), covering ribs R1B and R1. Could you post an image of the wing? 😊
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As I'm in the process of building a new wing, having crashed my Jocasta, I thought I'd do some checking within this thread. However, having gone through every post on this thread I couldn't find the answer I was seeking.
The Jocasta is stated as having a 60" wingspan. However, measuring both the wing physically and the plan show it to actually be 69"! Measuring the two wing halves (from the plan) minus the centre section would still give a span of 65". So, should I make this new wing the same size as the old one (69" or should I make it 65"? Alternatively, should I shorten the the two outer panels so that the wing comes out as 60"? What was/is the wingspan of the original Jocasta?
My first wing (at 69" only just fitted in my car. As I'm thinking of making this one flat or at least with reduced dihedral, it will be more difficult to fit it in my car (dihedral making the wing slightly shorter, tip to tip).
Edited By Colin Anderson on 01/06/2015 01:23:58
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Best of luck with the maiden Hannes. Looks like you've made an excellent job.
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You've made a really nice job of that mate. It looks really nice. 😊👍
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There is no cure, Glyn! You're doomed! Doomed, doomed, doomed......
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Well done Mowerman. 😊
Mine needed a lot of downtrim, also. I put quite a bit of lead in the nose - 80 g, if I remember!
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Glyn,
I used four tiny magnets from Maplin (two each side) for my hatch. These are not too strong, but they do retain the hatch very well. The hatch remains in situ even after a crash, yet can easily be opened with very little effort. Trust me, it works! 😊
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Give them a ring, Glyn. They are very friendly and helpful people; I'm sure they can help you out. 😊
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Posted by monty2 on 16/05/2015 16:32:01
Made up my mind as a beginner for the 2nd time will buy a 2nd trainer while I finish my Jocasta. its taking longer than I expected. I must get back flying for the summer. Winter up here in the North ain't fun
I know where you're coming from Monty. I too am a beginner. I built a Piper Cub last year to learn on, but had to move clubs, because I wasn't getting enough instruction. I took my Cub to my new club and had some flights, but something went wrong and it got crashed. It was decided by my club that I'd be better off learning on electric rather than IC and I gained my solo using a borrowed Wot4. As I was only cleared for electric I decided that the Jocasta would be ideal. I finished the build awhile back and was very pleased with it. However, I made 9 successful flights and then mysteriously it became unflyable, crashed and broke a wing. As it broke at the root I was able to repair it and was back in the air after a week. After adding the equivalent of a church roof to the nose it again flew and much better too! Again I made many successful flights, but found landing on our strip difficult; it's not that wide and I was using the entire length to land successfully! Our club site is on a farm so we have plenty of room to fly, but only a short strip to land. Landings therefore have to be fairly precise; not easy for a beginner. The Jocasta is a lovely plane to fly and I find it easy; although in windy conditions I find it quite a handful, especially when it comes to landing. Last week something went wrong and I again crashed, completely destroying the wing! I've now got to make a new one.
Obviously, as a beginner, I need to become more proficient with my landings. I'm fine with take offs and confident in my flying, even managing a few stunts. My landings though are sometimes good and sometimes not, often needing several go arounds. So like you I need something else to learn on. Against my nature, but acting on advice from my club today I purchased a foam Wot4.
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Hi Andjo,
Yes, in theory I could rebuild the wing, but to be honest it would be easier and more practical to build a new one. I'm toying with the idea of building a new wing without dihedral. I've read recently that aircraft with dihedral, although more stable can be adversely effected by crosswinds. I'm also wondering if using a semi symmetrical aerofoil might make it less "floaty".
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That looks really nice Andjo. I think your finishing method suits Jom's design perfectly.
Sadly, I crashed mine today, totally destroying the wing. It was flying beautifully, but during finals it began to drift towards the trees (there was a crosswind); as I tried to bring it back towards the strip it wouldn't respond - I have no idea why. Exactly the same thing happened to me last year; different model, different TX/RX. 😕😳
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Glad to return the favour. I've had much help myself along the way from forum members.
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Glyn, may I ask a daft question? Did you build the two fusalarge halves over the plan? The reason I'm asking is, looking at your image, things don't look right. It appears that you have the uprights inboard of the longerons, whereas they should be between them, as are the diagonals. It also appears that you have a break/joint at the leading edge of the tailplane platform. If you build the two fusalarge halves over the plan, then each half must have an upright at the rear and therefore there will be two making up the sternpost. This is certainly the way I built mine.
The screw on holding brackets for the main undercarriage are called saddle clamps. You should be able to obtain them from any decent model shop (although mine seems unable to get them).
Page 11 of this post shows my method for steering the tailwheel (it's not the only solution). Note: the long piece of wire extending rearward has not been cut to length in this image.
Edited By Colin Anderson on 07/05/2015 10:07:59
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I think Glyn's question is an interesting one. Yes, the free plan is fine for building from, although there were several mistakes of scale on this one. It's interesting that the Jocasta plan was selling for £12 (reduced to £6), yet you can buy the back issue (October 2014) for less! This does suggest that there must be a difference between the free plan and the one you can buy.
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Well, after altering the decalage, by adding positive incidence to the tailplane - which I had to repair anyway - restating the down thrust and adding the equivalent of a church roof (80 grams!) to the nose, I'm happy to report that my Jocasta is now back in the air an flying very well. It now flies pretty much hands off. It still needed some down trim on the elevators as well as right rudder trim, but it no longer stands on its tail when power is applied. Now all I need to do is perfect landing it. In my hands it's still reluctant to come down to earth!
Unfortunately a hard landing cracked the undercarriage and broke the propeller. Although the undercarriage was cracked, with a borrowed propeller I was able to get a second flight. I find it better on an 11" x 8" rather than an 11" x 6" (recommended by 4 Max). I never got to make a third flight (probably just as well with a cracked U/C! ) due to a dry solder joint to the ESQ which thankfully showed up before flight!
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Hi BEB,
Have just found this thread looking for possible solutions. I've recently built Jim Newbury's Jocasta. If you don't know this plane (why would you) it's a retro style high wing trainer. It's different to what I learnt on (a borrowed Wot 4), but quite easy to fly; at least it was! I made 9 successful flights with it. It had a tendency to climb sharply under power, but at around half throttle it was manageable, although I found it hard to bring to earth. My last landing was a hard one in the cabbages, which bent the undercarriage and tore the mounts off. Following this incident I decided that more down thrust was needed. Having done this and made the repairs it was back to the flying field.
Back at the field I made two flights; neither were good, the second being a disaster. On take off the plane climbed almost vertically! And this with the added down thrust. Once up it was pretty near unflyable. It responded poorly to ailerons and our club instructor had to rescue me and brought it in on rudder. On inspection we found I'd reversed the aileron leads! This was promptly rectified and I took it up again. Again an almost vertical climb and again the plain was unresponsive; the flight culminated with a spiral into the ground (which broke the wing).
Now down thrust, I believed, should have made the plane fly better. Clearly, it didn't; I've since reset this to what it was. My thought is, was the wing incidence/ decalage wrong to start with? When I placed the wing at the field perhaps I did not seat it correctly and made an unknown fault worse?
All the above is a rather long-winded way of asking: would wildly incorrect incidence/decalage have caused these problems? If it's not this then I don't know what to look at. It's got me baffled. I'd like to enjoy flying this plane, rather than crashing it
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Hi Jim,
Thanks for this. In total my Jocasta made 9 successful flights before I dropped it into the cabbages. The only damage sustained on this occasion was a bent undercarriage, which also broke the front saddle clamps. Although technically any uncontrolled landing is a crash, this was a very gentle one; I'd cut the power on the approach (I know I shouldn't have) and missed the strip.
In my inexperienced hands I felt the model flew pretty well, if different to what I'd got used to (I learnt on a Wot 4). It did have a tendency to climb rapidly under power and our club instructor (who trimmed it out for me) had dialled in a visible amount of down elevator.
After repairing the undercarriage and adding (from what you've told me) additional down thrust, I neutralised all the trims - perhaps I shouldn't have! From this point on the model became unflyable; even our club instructor found it difficult. I'm coming to the conclusion that down thrust is not the problem. From my free flight days I remember that once the CG was right the model was trimmed by altering the decalage. Perhaps when I assembled the model at the field the wing might not have seated properly and thus altered the decalage? Perhaps the decalage on my model is not as it should be in the first place? I know there are special tools to check this, but I don't own one.
It's going to take me a while to repair the wing (I just can't seem to get the root ribs to mate properly). In the meantime I'm going to return the motor back to its original settings (although I'll probably leave the side thrust in). I'll also need to find a way to check the decalage. I've convinced myself that this is probably at the heart of the problem.
Jocasta
in Own Design Project Blogs
Posted
Hopefully you'll now be able to see my new wing (above) that I mentioned in a post above (where the image doesn't show. I've added the glass tape since this image was taken. All I have to do is cover the wing now.
As mentioned above. The ailerons and wing tips are salvaged from the crashed wing. I've also reduced the dihedral.