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Jack Plane
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« Reply #200 on: March 04, 2019, 02:06:44 AM » |
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I have an untrimmed Jodel waiting so you may have motivated me to get going.
Ricky
Go Ricky! Any pics? |
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Jack Plane
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« Reply #201 on: March 06, 2019, 02:44:47 PM » |
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The difference eighteen months makes... He's now determined to do it all on his own - not that I previously did anything more than guide him, just that he now wants ownership of the whole process, planning, making and all.  |
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Russ Lister
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« Reply #202 on: March 06, 2019, 03:19:10 PM » |
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Great stuff .... get 'em 'ooked!
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TheLurker
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« Reply #203 on: March 06, 2019, 03:33:32 PM » |
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Good to see No. 1 Apprentice back at the bench. Pass on my regards.
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DHnut
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« Reply #204 on: March 07, 2019, 03:53:46 PM » |
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The photo of the Jodel is attached. It is still awaiting outddor trimming. I tried some initial flights at our indoor hall and decided it was a bit risky. I just need a little less wind. The weight is 21 grams including rubber, and the noseblock is held in with magnets.
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Pete Fardell
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« Reply #205 on: March 07, 2019, 05:55:10 PM » |
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Looking very nice in the sunlight, Ricky. 21g sounds alright too.
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OZPAF
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« Reply #206 on: March 07, 2019, 06:19:04 PM » |
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Excellent work on your apprentice Jack. Ricky's nice shot of his model in the sun should be an inspiration.
John
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danmellor
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« Reply #207 on: March 07, 2019, 07:38:27 PM » |
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My Jodel has been stuck in it's box for around 3 years. I keep forgetting about it! I must take it to the next Alfreton bash and finally get it trimmed. All I have to do is try and remember what it was doing last time out...
Lovely little design and some nice finished (And being finished!) examples on here!
Cheers,
Dan.
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DHnut
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« Reply #208 on: March 07, 2019, 10:12:33 PM » |
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Dan,
I can empathise with that sentiment. Look forward to hearing how it goes. I have finall resorted to a log book of sorts when I remember to note things down. It certainly helps on rubber size as I like to strip a variety of sizes and maintain an even number of strands for braiding if needed. By the way the heavens have opened after about 6 weeks without rain but a nice summer.
Ricky
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Jack Plane
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« Reply #209 on: March 08, 2019, 02:35:57 AM » |
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Ricky, very nice Jodel and excellent weight for VMC model! Nice sunshine too!
We've got a westerly airflow over the British Isles - the sort that parks itself and doesn't move for a long time - but its still late winter, the earth needs the rain, deadwood needs blowing down, and I'm on a work deadline so can do without any excuses to skive off for outdoor trimming or slope soaring!
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Jack Plane
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« Reply #210 on: April 21, 2019, 03:45:53 PM » |
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A jolly intense week guiding the Kid (organising, demonstrating, cajoling, bollocking, hugging, encouraging, giving lots of breaks) to complete his VMC Jodel in time to maiden in today's superb trimming weather - the pressure was on as tomorrow onwards forecast to be meteorological business as usual. Making started in Summer 2017 when he got bones made, but was then put away and he only got going again a few weeks' ago when he decided he was going to have a go at the Nats!  Footage here of one of the early trim flights on 3/16" rubber (185 thou) 1.5 x hook to peg: https://photos.app.goo.gl/iBgL623jfjG5L3zy6550 turns (50% of max/break) will do 15secs from hand-launch, but this feels slightly too aggressive and really think we ought to prepare a similar length of 160 thou for the Indoor Nats next weekend. Weighs in at about 35g (27.5 airframe + 3.5 rubber + 5 nose-lead), a loading of about 0.56g/sq in so not too bad for a big indoor space...? Jon |
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« Last Edit: April 21, 2019, 04:06:26 PM by Jack Plane »
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Jack Plane
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« Reply #211 on: April 21, 2019, 04:05:57 PM » |
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He really wanted to do a good job - including moulding a balsa cowling! - all with a broken arm courtesy of the school ski trip We doped in the back of the car with all the doors open and a breeze blowing. The pilot is his dog (at his mum's house)!  |
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TheLurker
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« Reply #212 on: April 21, 2019, 04:28:41 PM » |
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Flies better than anything I've ever built. Well done to the No. 1 Apprentice.
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DHnut
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« Reply #213 on: April 21, 2019, 06:41:57 PM » |
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The Jodel also looks promising as well. I am using .130" for the initial trim flights and it looks promising with a total weight of 21.5 gm but may need a little more . I have also had to add weight to get the CG right. There was a need to get a warp out of the cetre section, now done. We have just had a magic morning yesterday with no wind flying Cloud Tramps.
Ricky
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Pete Fardell
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« Reply #214 on: April 21, 2019, 06:56:55 PM » |
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Very fine effort indeed! Looking forward to seeing it in action.
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Ex Member
Guest
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« Reply #215 on: April 22, 2019, 06:29:20 AM » |
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Boy done good! Andrew |
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Jack Plane
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« Reply #216 on: April 22, 2019, 08:28:13 AM » |
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Thanks guys - I'll pass on your comments!  Made a new motor from 165 thou as the 185 seemed a bit too aggressive, and managed to get out early this morning for brief tests before the wind piped up. Gentler flights but still a reasonable initial climb etc on 65% of max/breakage turns. Needed to reduce right-thrust (was 3º previously) to compensate and keep the circle respectable, and also needed to assert a tad more down-thrust. Gentle gliding turn seems fine and model appears to have reasonable enough longitudinal stability. We'd glued the rudder on with a very slight left angle, but the model needs a proper card tab to nail the turn. A gurney along the underside TE of the left tip plus another one the same length just inboard of this seemed to do the trick of keeping the inner wing up. Had to curtail the session when the breeze established itself more fully (those upturned tips really catch the wind!) but I think we're good with the 165 and we can finalise trims and hopefully put it all together indoors at Walsall next Saturday afternoon! |
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OZPAF
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« Reply #217 on: April 22, 2019, 09:39:10 PM » |
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Your apprentice has done a great job on the Jodel Jack and it flies well. You've done a good job training him - well done.
John
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danmellor
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« Reply #218 on: April 28, 2019, 05:28:05 PM » |
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That's it over for another year! Great day, even though I didn't manage to enter anything this year. Some superb models and flying and a big thanks to the organisers...
Cheers,
Dan.
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Russ Lister
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« Reply #219 on: April 28, 2019, 06:18:56 PM » |
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As you say Dan, great day. I was happy to have timed all the open and kit scale flights today and the red cross, non-qualifying flight paddle didn't get much use. |
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OZPAF
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« Reply #221 on: April 29, 2019, 09:17:50 PM » |
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Nice flights Jack. The Bristol finally tamed and all the flights looked good. The Jodel looks nice - a good effort from your son and there is more performance there I feel. The Halberstadt seems to only need the slightest extra downthrust , although it still did very well.
John
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Jack Plane
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« Reply #222 on: April 30, 2019, 04:19:04 AM » |
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Cheers John Yes, there's more to come from the Jodel. 3/16" is roughly the right grunt, but needs to be split into something like two loops of 3/32" to dampen the initial burst (cured on the day by winding then backing-off an extra 50 turns), and increase its length from 1.5 to 2.0x distance for a more satisfying duration. I'm certainly thrilled for Isaac, who's well made-up by his own achievement and participation! The Halberstadt did nicely enough in 'prototype' form, but needs a few measures to get it properly fit for duty at the front: - Move the peg forward an inch to the cross position, so it doesn't have to carry so much nose-weight, but keep the motor length the same - currently 1/8" (125 thou) 3.0x distance to existing peg-position, so will end up being about 3.5x or so, hope to get away without a bobbin!
- Increase the prop size and blade area as currently losing huge amounts of rubber energy, still loads of clearance for ROG, experiment with pitch etc
- Increase down-thrust to match these changes
The kit plan showed zero incidence on both wings. I took a punt and built in 2.5º for the top wing and 1.5º for the bottom (same as the Scout). As can be seen in the video, the 1º differential certainly tames the stall albeit at some cost to performance, but the overall degree of incidence of both wings might explain its excessive pitch-up tendency..? There's a limit to how much down-thrust I can put in without the hook jamming under the dummy engine, so am considering de-bonding the whole lot and re-setting the wings at 1.5º and 1.0º respectively? Or maybe just experiment with down-elevator trim first!? I've got a comprehensive set of build photos, and wondering whether to do a full build-thread. Would people like this? |
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OZPAF
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« Reply #223 on: April 30, 2019, 08:48:58 PM » |
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I'm certainly no expert in this area Jon but perhaps the Jodel would do well on slightly lighter rubber, with a wider turn for indoors anyway. Certainly a longer motor. However the owner/builder has the last say in this area Great effort. The Halberstadt is flying so well and it seems that your incidence setup is working. It would be interesting to see how lower incidence settings would work. Actually if it is relatively easy to change the tail it may be best to add a bit of positive incidence(very small) to trim the model to fly at a lower AOA, while still retaining the difference between the 2 wings. This would also add some down thrust effectively and may need the CG moved back slightly to regain the glide? It may be worth trying this with a tab on the tail, slightly deflected downwards to see if this would help. Also yes I would like to see your build on the model. John |
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Squirrelnet
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« Reply #224 on: May 01, 2019, 02:12:44 AM » |
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I've got a comprehensive set of build photos, and wondering whether to do a full build-thread. Would people like this? I would love to see how you put it together Jon, you can't build a nice build thread |
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