Junior 60 Electric Build Query

[Mike Hardy]

Hi, Started this kit a couple of years ago and so far completed the wing and most of the fuselage.

I have read of late on here that the rudder and elevator area needs to increase slightly to improve handling, does anybody have details of this mod.

I understand the fuselage nose length needs to be increased by 20mm to help with the C and G when using modern (lighter) induction motors.

Mike

[Mowerman]

In the latest edition (September 2014) Peter Lowe gives details of mods to his J60 electric build.

Fuselage lengthened by 0.8" Controls increased to same as later Flair kit.

My J60 (i.c.) from flair kit has - rudder 6.75 x 3.5" elevator .75" wide across tailplane halves.

Hope this helps.

Edited By Mowerman on 01/08/2014 14:19:47

[Mike Etheridge 1]

Back in 1962/3 when I built my Keil Kraft Junior 60, as proportional control was not available you had to rely on a rubber powered escapement that gave you full left rudder,neutral and then full right rudder and vice versa. As a result the rudder was substantially smaller than in the current Flair (1955) and Ben Buckle (1946) versions of the plane. With modern radio fitted the small rudder never seems to be a problem to me as my Junior 60 still flies OK. As for nose weight, to get the centre of gravity right I had to add a half of a pound of lead to the nose of the plane. This is also the case with a Ben Buckle Junior 60 I have.that shares the same wings as the Keil Kraft plane. I am not sure why Albert Hatful decided on such a short nose for the plane other than it may have balanced OK with the spark ignition engines available then? The nose was substantially lengthened on the Super 60, and on my Super 60 I had to add weight to the tail.

[Mike Hardy]

Thanks Mowerman and Mike, do I take it I build the tail plane as per the Ben Buckle kit of 2012, bit confused here.

Mike.

[Mowerman]

There you have the two options, you can take your choice. With the bigger control surfaces you can always reduce the throws either at the transmitter or in the linkages.

[David Davis]

Posted by Mike Hardy on 01/08/2014 17:02:01:

Thanks Mowerman and Mike, do I take it I build the tail plane as per the Ben Buckle kit of 2012, bit confused here.

Mike.

The Ben Buckle kit is based on the original 1946 free flight design and has a smaller rudder than the Flair kit which is based on the 1957(?) re-design. The Flair kit has a wider fuselage and stronger wing than the Ben Buckle kit. To increase the rudder size to the same as that of the Flair kit, simply drop a perpendicular from the highest point of the fin and build a rudder from that point rearwards.

These two pictures may help.

[Mike Etheridge 1]

Mike,

My feeling is that regardless of your approach to making the Junior 60 it is a superb flier and can of course free- flight as my original did at Epsom Downs. A few years ago a club friend had an electric Junior 60 and it was most impressive. Despite not being an aerobatic plane as it can fly without much control input you can take it safely to greater heights, and I am convinced with the engine shut down you can gain height in thermals something you cannot do with an aerobatic flying brick.

it it was me I would stick to the original plans.

MJE

[Ponty Bri]

Aah! yes the Super 60 most of us old codgers had one, mine ditched in a lake and when rescued all the wood glue had gone soft. I straightened it out, put it on the nightstore heater overnight and flew it again the next day.

Happy days. Great plane.

Brian

[David Davis]

Posted by Ponty Bri on 01/08/2014 20:17:12:

Aah! yes the Super 60 most of us old codgers had one, mine ditched in a lake and when rescued all the wood glue had gone soft. I straightened it out, put it on the nightstore heater overnight and flew it again the next day.

Happy days. Great plane.

Brian

Grrrrrrrr!!!!

The Super Sixty was a different model! Why do people, even the "old codgers" constantly confuse the two? The only things they had in common was that they were both made of balsa wood, both produced by Keil Kraft and both had the word "Sixty" in their title. The nose is longer on the Super Sixty, the wing and tailplane are different shapes, they have different aerofoils, the tail on the Junior Sixty is on top of the fuselage and on the bottom of a Super Sixty. Need I go on? Picture of my three-channel Super Sixty below.

Having got that off my chest, I had a similar experience to Brian's with my Junior Sixty, the first successful r/c aircraft I ever built. I was very much a novice pilot and living in North Devon on the 1980's. I had taken the afternoon off work and gone to the flying field with the model, not the one in the photo above, that was the second J60 I've built. The first was powered by an Irvine 21 and covered in old Olive Drab parachute nylon! very colourful! There was only one man at the flying field, a holiday maker who hadn't asked permission to fly from our field. I explained that I was a novice pilot and had never either taken off or landed my model. He agreed to take off and land the model for me and to hand me the transmitter once the model was at altitude. It took a few minutes to get the engine started but when I looked round, he had gone!

Being an old free flight modeler I knew that the Irvine produced sufficient power to enable the model to take off provided I kept it into wind. It was very calm, so I faced it into wind pushed forward the throttle and the model took off. It required full down trim to stop it from climbing all the time. I resolved to fly it till it ran out of fuel then glide it down. Once the engine cut it went into quite a steep dive and disappeared behind some trees. I heard the impact and fearing the worst, set off to retrieve the model. I found it in a small pond! The tailplane was out of the water and the fin was acting like a sail. I waited till the breeze blew it close to the bank, then I pulled it out. I had used waterproof PVA in its construction and did not even think about the effect that its bath would have on the joints. I removed the receiver, placed it in the airing cupboard and flew it again the following weekend!

The reason that it went into a dive was that I had full down trim on the elevator. Once the engine cut, the model dived and I was too inexperienced to neutralize the trim and control the glide. Lesson learned. Happy days!

I eventually sold the model to my cousin but he never flies it. Maybe I'll buy it back. Hmmmm.....

[Ponty Bri]

Thank you David for that correction. The silly thing is that the model I had WAS the Junior 60 but the mists of time had made me forget. I couldn't aspire to a Super 60. Not until now had I remembered that there were indeed two 60s.

Brian

[Mike Etheridge 1]

Well David is right about the differences between the Super and Junior 60's, the former being a much updated shape at the time in 1961. However the wing chord dimensions match and if you match the wing platforms of the two planes you can as I did utilise the same wing on both models. See this video of an E-bay very much re-built Super 60 with my 51 year old Junior 60 wings: https://www.youtube.com/watch?v=rGLbsqArse4&list=UUPA9CubbfRE5tIf17IbZ1_A

At my club last year a flier lost control of his enlarged Junior 60 the Majestic Major as the closed loop on the rudder failed. The plane then flew off from Bartons Point on the Isle of Sheppey and landed out of sight in the Thames Estuary. Fortunately it was spotted by someone in a boat and recovered. I am not sure of the plane's current status?

Edited By Mike Etheridge 1 on 02/08/2014 09:17:10

Edited By Mike Etheridge 1 on 02/08/2014 09:25:52

[Former Member]

[This posting has been removed]

[David Davis]

I agree with the policy of keeping the nose the same length MKF but disagree with you about the Ben Buckle version being superior to the Flair and that the "best way is rudder only."

The Flair version has a much stronger wing structure, what's not to like about that? As for rudder only flight, that's alright for single channel enthusiasts but us lesser mortals prefer to have an elevator to allow for some penetration into the wind and to effect a three point landing.

It's 2014 not 1954!

[Mike Etheridge 1]

A club member said he preferred the appearance of my Ben Buckle 1946 Junior 60.

David is right about wind penetration, to keep the nose down into wind with the KK Junior 60 the only way I could manage it without an elevator was to throttle back the engine which was something I could not do when the plane was served with single channel radio. However landing the Junior 60 dead stick or otherwise was always a piece of cake without an elevator and my plane never nosed over.

I have a wing kit for the Ben Buckle Junior 60 which I have never made up, but if I did I would strengthened it as has been recommended by others. I also have a dismantled aileron wing from the e-bay Super 60 but the building standard is so poor it is almost a pile of scrap. However if I do refurbish it , I can use it on both the KK Junior 60 and Super 60, and at a pinch on the Ben Buckle Junior 60?

[David Davis]

If you need extra weight in the nose with an electric powered Junior 60 Mike Hardy, you could always use a much bigger LiPo, that way you'd get longer flights too.

My original model had 1.5 lbs of lead in the nose to get the C of G right yet the little Irvine still flew it. It was better in a wind too!

[Mike Hardy]

Thanks Guys, firstly there are some great junior 60's shown in this thread, I am truly humbled by all you master builders who have commented.

What concerns me is the possibility of adding 1.5 Lbs. of ballast up front to achieve a balance about the wing spar. the additional nose length should reduce this ballast especially if the li-po can be positioned right up front. I can do a moment calc. to give me some idea knowing the weight of the electric drive components. Another worry is for the apparent tendency (comments on here) for the wing half's tips to meet in mid air!! Now my wing is already built to the Ben Buckle plan so just how do I extend the dihedral brace into a further wing bay? without drastic surgery.

Mike.

[David Davis]

Mike

1. Regarding the 1.5 lbs of lead, you will only need this if you build the tail out of heavy balsa as I did. Once I'd made a lighter tail I was able to remove all of the lead.

2. The Ben Buckle wing seems to be quite adequate for ordinary vintage style manoeuvres.

3. You could probably get away with mini servos too on this model and save a little more weight.

[Mike Etheridge 1]

My 51 year old KK junior 60 wings which are nylon covered have never folded but at the same time they have only been looped once when they were attached to the Ben Buckle fuselage.

A couple of years ago I finalised repairing and electrifying a Mercury Matador which belonged to my nephew who had scrapped it. The wings had folded when my nephew tried to recover it from a thermal. I re-built the wings as original but with balsa sheeted leading edges similar to the Junior 60. I also installed flat spruce spars top and bottom beside the balsa spars plus some additional bracing linked to the spruce. The Matador has only flown a few times and never stunted however and still survives in my loft.

.