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Junior 60 incidences

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Doug Campbell01/10/2016 07:13:53
89 forum posts
2 photos
Posted by kc on 08/09/2016 11:01:54:

Let's not clog up this thread with further discussion on this aspect but I will just quote the words of my colleague who built the modified J60 . Yesterday when I was asking what changes he had made he told me about the changes and then said " I don't know how we used to fly these on single channel ! " but of course he did know because he had done it and what he really he meant was the flying is now more enjoyable. That's what it's about. Enjoying the flying.

Edited By kc on 08/09/2016 11:03:24

Come off it KC, only you allowed to comment ?

I like all types of models but when I start reading that the wings, tail, and fus have been changed is it really anything like the original model? As for improvement, he had a version that flew on single channel but since he messed with it he wonders how. Is this improvement or has he messed up a fine flying aeroplane?

Percy Verance01/10/2016 11:04:37
7935 forum posts
152 photos

Junior 60 a fine flying aeroplane? I'm struggling a bit with that one. We all have our views and opinions though, so hey ho, each to their own.

Mike T01/10/2016 14:42:05
400 forum posts
28 photos

A balmy summer evening, you cut the throttle and she glides down to alight just on the threshold. A little dab of throttle and a touch of left rudder (aileron) and she trundles along the runway on her left wheel. A little dab of right and she trundles along on the right. At the end of the runway, you open the tap and she soars up and away - into the easiest rolling circle ever...

Bob Cotsford01/11/2016 16:40:54
7791 forum posts
432 photos

I've just flown a J60 Ebay purchase for the first time today and it needs a number of changes to make it into a workable model. It looks quite old, one servo being a 128 the others 148s, and for power it's got an OS FS26 however it looks to be covered in 'Antique' tex which I didn't think had been around that long. I actually bought it for the OS FS26, a lovely motor that seems to be running sweetly enough but it is very marginal on power for this model. That could be in part because of the enormous quantity of lead in the nose and on the U/C fitted to get the C of G forward enough for flight. The rudder has a long torque arm passing down about 1 1/2" and coming out of the fuselage side under the tail - this with a banded on tail making the banded on bit redundant. This and the elevators are driven by 3/8" hardwood dowels with a good length of tape wrapping on each end. Even with all the lead up front it still needed half down elevator to achieve level flight - not good!

So, I can get rid of the 3/8 dowels and use closed loop for the rudder, maybe for the elevator too? Glue on the tail, perhaps shaving 1/8" off the rear fuselage to reduce the down elevator needed. I can get rid of the old plastic servo tray, that would allow me to move the servos forward by about 3". Bigger motor? A little more power would be nice but not so much as to loose it's character.

How much lead have you all needed to get it to balance?

Bob Cotsford01/11/2016 16:55:04
7791 forum posts
432 photos

Thinking about it, I could reduce the lead by a third by moving it from the U/C area to the front of the engine bay.

If it will all fit!

cymaz01/11/2016 17:06:51
8452 forum posts
1160 photos

Sc 30fs I had in mine...great little motor. It needs as much lead as is required...if that doesn't sound too odd.

Closed loop on rudder and elevator, love the idea, very classy. Miss it out on the throttle though.

I added about 1/4- 3/8 to the TE wing seat. That stopped it flying like a home-sick angel.

Enjoy the phut- phut of the little 4 stroke as you quietly and gracefully do T /G's on a warm, calm summers' evening...ah bliss

I crashed mine when the wings clappedcrying

gangster01/11/2016 17:21:33
916 forum posts
16 photos

Bob. Yes agree it's best to get the lead at least to the far side of the bulkhead 3/8 dowel sounds a little clumsy but not Terrible 1/4 square hard balsa would be fine. I am a little surprised it is underpowered with that motor. If you want to Fly it through the sky even like a 40 powered trainer you will be making trim changes for the rest of your life. The J60 is an elegant gracefully old lady. Fly it with minimum power and enjoy its beauty and grace And that is coming from someone who for most of his modelling life thought that all models 60" and below should have an Irvine 60 up front

Bob Cotsford01/11/2016 18:04:41
7791 forum posts
432 photos

It would probably be fine with 1/2lb of lead removed! I do quite like my vintage models to float around, my Eros certainly does - 84" on an OS FS48 and it doesn't want to land, even at tickover. Nice for thermaling on a sunny day too.

David Davis02/11/2016 06:16:10
3300 forum posts
563 photos

Bob, I agree with Gangster, get as much weight up-front as you can, I have the Rx battery under the engine in mine. Furthermore, the engine in mine is an HP VT 25 fourstroke which only just powers it. I've heard these engines described as, "Heavy as a 40, power of a 10!" but the extra weight is handy in the J 60's short nose. Once in the air, the model flies extremely slowly gaining a few feet on every circuit. My friends in my French club have never seen anything like it! surprise.

As I have stated in previous posts, the Junior 60 was designed as a free-flight model so that providing the engine was running, the model would climb. With engines with a throttle it is possible to reduce the power output to such a degree that the model will fly straight and level or even to descend under power.

Picture of the fuel-soaked veteran below, warped wing and all but without the engine fitted.

junior sixty (1).jpg

Bob Cotsford02/11/2016 10:46:47
7791 forum posts
432 photos

I think I may just strip this model out and do a bit of weighing, then do a fresh ground up installation and see what difference I can make to it's AUW. Winter is coming and I'm on long term sick leave so there's plenty of time. I'll leave the external 'patina' 'cos I can't be doing with a full on restoration but it'll be an interesting exercise to slim it down.

Any thoughts re gluing the tail on? I can't see any real need for it to be removable as I won't be stripping it down to carry on a pushbike and getting rid of the dowels and bands will save a few precious grams from the back end.

ken anderson.02/11/2016 10:54:16
8395 forum posts
772 photos

here's the ne...1 version...OS 30 4/st...and 1/2 lb of lead in the nose....

ken lead dept.

Bob Cotsford02/11/2016 11:04:18
7791 forum posts
432 photos

1/2lb = 8oz=~240gm. Say a conservative 3:1 moment ratio for the effective position of the pushrods - wonder if the two 10mm pushrods plus 2mm threaded rods each end in mine weigh more or less than that 80gms? Might be I could save that much lead just by going closed loop! It will be interesting to see.


As near as I can make out on the kitchen scales the complete fuselage and tailplane weighs 4lb 11oz at the moment, so my target is to beat 4lb 3oz.

Edited By Bob Cotsford on 02/11/2016 11:08:14

PatMc02/11/2016 12:16:18
4134 forum posts
518 photos

Before I converted my Jnr 60 to electric the OS25fp engine + nose weight was about 8.5oz [i.e. less than the weight of an OS26fs]. Most of it's ic powered flying was with an OS max 25 fitted with home made silencer, same weight when ballast added.
But my Jnr has the cg over 1" rear of the plan cg & is still a sedate flyer. I arrived at the cg by progressive incremental reduction of nose weight used for the first flights. IMO the cg position is virtualy optional due the tailplane area being so a large compared to the wing area.

motor lengths.jpg

Final ic engine used - OS 25FP.

scan_os max 25 (1024x768).jpg

Original OS max 25.

The refurb thread of my Jnr includes info on fixing the tail with a single small screw & ply tongue, [IMO better than gluing, neater & lighter than rubber bands & more secure than both] also info on pull-pull for rudder & elevators.

Braddock, VC02/11/2016 12:52:57
1600 forum posts
68 photos

Irvine used to sell big brass prop spinner nuts that weigh about 80 grammes iirc, they go on an os 26 just fine and everything else with a 1/4 unf/6mm threaded prop shaft.

They put the weight exactly where you need it, it also acts as a flywheel to some degree, enhancing the slow running qualities, already great, of the little 4 stroke.

Glue the tail bits on and do closed loop for rudder and elevator and you may not need any more lead though with solartex it may be necessary.

Fitting the battery beneath the engine is one way of avoiding further lead though it can get oily unless you bite the bullet and modify the 26 fs by plugging the oil vent and drilling a small (1.5mm) hole from the rocker chamber into the inlet tract then sealing the rocker cover with hylomar or similar. You may have to richen up the slow running needle slightly to compensate.

You used to be able to buy rubber tyred, alloy hubbed wheels that helped as well.

Personally I've never felt the need to have wing bolts on mine but the one I've seen with them looked really neat.

As far as flying abilities of the J60, it's a marvellous way of learning how to thermal, some of my longer flights have been made after the engine cuts.

Braddock, VC02/11/2016 12:52:59
1600 forum posts
68 photos

double post, oops!

PS I go along with patmc, c of g is very conservatively sited on the flair j60, wouldn't want to comment on the BB one.

FWIW my first J60, 1955 - 56 flew with an ED racer, covered in tissue and doped ( the plane, not the engine). The racer is no way a match for the os 26 fs. 


Edited By Braddock, VC on 02/11/2016 13:05:06

Edited By Braddock, VC on 02/11/2016 13:08:16

Edited By Braddock, VC on 02/11/2016 13:10:18

Don Fry02/11/2016 14:29:02
3491 forum posts
40 photos

I used to have one, 20 size Magnum 2st, Slec 4 oz tank, mounted upright in the engine bay, then servos right at front in the cabin, battery underneath servos, close loops to the tail, clevises at the servo end. With that installation it needed no lead. Plan built, 3 lbs 12 oz, solartex covered. Very nice flier, about 40 minutes on the four once tank.

Mike T02/11/2016 17:20:10
400 forum posts
28 photos

Weight at the front is the key (and next to nought at the back of course). Mine has an OS40FS, Solartex'ed wings and fus., Litespan'ed tail. Servos, rx, tank and NiCad (yes, NiCad) all up front. No Lead!

The wheels are B&Q buggy wheels (NLA). A bit OTT perhaps, but they are light and the proportions are just right.

j60 (3).jpg

Bob Cotsford02/11/2016 17:21:41
7791 forum posts
432 photos

Thanks for the comments. Pat, i like the bolt on tail, I have some 3mm inserts and nylon bolts spare from the Eros tail which is held on by 4 nylon bolts into inserts in the tailplane.

I doubt it will come down below 4lb, but I'd be happy if it lost 1/2lb or a shade more. Still, I have all winter to play with it.

Bob Cotsford03/11/2016 21:40:15
7791 forum posts
432 photos

Thought I'd better drain the fuselage after the bung came out of the tank the other day, so while I was at it a bit of dismantling took place.

Pushrods - 2.3oz. 128 and 148 servos in the old Futaba plastic tray - 5.5oz - all behind the CofG.

Lead (between and on the U/C legs) 1lb 0.2oz. Bit of a daft place to put it!

Unfortunately despite what looks like a recent coat of Poly-C or similar the half former holding the rear U/C member is rotted, cracked and pretty moth eaten with some poorly positioned slots - previous wiring routes? I'll have to try soaking the nose in hot water and detergent tomorrow to see if the oil washes out. At least it's not bare wood. If there's anything clean enough to take glue it'll need a doubler adding to take the U/C. I don't think I need to worry about keeping the rework light! At least the aluminium hub balloon tyred wheels are quite nice.

onetenor04/11/2016 04:55:30
1893 forum posts

Why not try making a smaller lightly built tailplane.Say a 1/4 smaller. than standard. Should improve things John

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