Trimming tips for the electric version of the Junior 60

[PatMc]

300 Watts would be about right for the Yulon & by coincidence was the same power used in the first flights of my electric version.

Weight, I don't know but it's reasonable to guess that since it was built with competitions in mind it would have been built as light as possible, it was covered in tissue & the only hardware carried was the 5.5 oz Yulon.
Mine OTOH is Solartex covered, carried circa 8oz radio gear with linkages etc + 12oz of motor & battery. It was converted from IC with no attempt to save on weight & came out RTF at 3.75lb
On that basis I'd guess 2.25lb would be realistic for the 1956 model.

 

Vertical, I didn't claim. Near vertical was my memory & since the model would have been launched (BTW it was hand launched) directly into wind much of the horizontal airflow element would have been vertical WRT the ground.

 

Fast, is of course a subjective term, in this case a comparison was intended to be drawn with typical modern vintage models. My Jnr 60 climbs noticeably faster than the average modern ditto, with climbs in the first 2 flights measured at 11.7 & 14.6 ft/sec respectively. 
Given the weight & power estimates of the 2 Jnr 60's then and now I think I can be fairly confident that my memory of the model's climb performance is reasonably accurate even after 65 years.     

[Skippers Walker]

Junior 60 Flying update: As a post script to the recent meanderings about trimming and flying an electric J60, mine has had a couple of lengthy flights now. 25g of weight added to the nose (75g total) plus 2mm of down thrust and easy on the throttle. Goes like a dream! Thanks for all the comment.

Looking forward to more calm relaxing Summer days ahead.

Cheers for now

Chris (SW) 

[Don Fry]

Pleased you are happy. I built my last one in the early eighties. Sold it on the 5th July 2005, to clear out the fleet for a house move. Bitterly regretted, as I still remember the date, but can’t remember the registration number of my car after eight years of ownership.

[DaveyP]

8 hours ago, Skippers Walker said:

Junior 60 Flying update: As a post script to the recent meanderings about trimming and flying an electric J60, mine has had a couple of lengthy flights now. 25g of weight added to the nose (75g total) plus 2mm of down thrust and easy on the throttle. Goes like a dream! Thanks for all the comment.

Looking forward to more calm relaxing Summer days ahead.

Cheers for now

Chris (SW) 

 

 

Hi Chris, did you ever finish the "Madcap" build  ?

 

Dave P 

[Skippers Walker]

Hello Dave I certainly did finish the Madcap (picture attached). The model is still on my bench awaiting a first flight. I have, as you probably may have seen from my recent posts, been concentrating on getting the Junior 60 airborne safely. The Madcap is the next in line then another 'lockdown' model a Tony Niijus Sky 40e!. Busy times ahead whenever the weather permits.

Thanks for asking, I hope that you are getting some flying time in now?

Cheers for now 

Chris

[Robert Davies]

Late reply!

I have aquired today two J60's. I currently fly a Black Magic with an OS 30 fourstoke. On take off it climbs around 45 degrees upwards or more in a breeze, Clark Y airfoil, lots of lift. Devil of a job getting her back from downwind on a breezy day needing up to max throttle and a handful of down elevator. I have mixed throttle and elevator, from around 30 percent percent throttle to add increasing down elevator. On the flick of a switch she will stay horizontal when I increase the throttle. I select this mix after take off, nothing like a STOL take off before layze cruising! Or leave the mix off on a calm day. I intend to set up the J60's the same way.

   By the way I have also set my rudder as a Primary control on the aileron stick. (Mode 2) I also have my rudder stick set to operate the rudder as well as I am used to maintaining heading with the rudder on " full house" models. BUT it must be remembered that operating both sticks at the same time doubles up on the range of movement so, One Stick At A Time!   Unless you have an answer to this...Spektrum DX8G2?

  If this has been  covered previously, my apologies as I've obviously missed it.

      Cheers, Bob.

[paul devereux]

A bit off-topic, but if anyone wants a free plan of the J60 (BB version) and a Radio Queen I have them, cost would be to cover the postage.

[Engine Doctor]

On 06/06/2021 at 20:55, Skippers Walker said:

Some really interesting but slightly confusing stuff guys. I'm not too sure if I should stock up on beer, buy a new chair or take a pin and stab at the text for a 'next step?

If there was one change to make to start with what would that one change be please?

Kind regards

SW

Next time you fly the J 60 take some 1/16 balsa sheet along . Pack up the trailing egde 1/16 to start with and fly it . If not enough and down trim is still required add another piece. Once happy with the set up make the packing permanent and fill along the wing seating area so wing seat is suported.

The Junior 60 was designed as a free flight model with a slow glider hence the high angle of attack / incidence of the wings. It apppears few plans have been altered to allow  for rc flying over the years as when the occasionally turn up at our field the same issue is present.

Enjoy the J 60 

[PatMc]

57 minutes ago, Engine Doctor said:

Next time you fly the J 60 take some 1/16 balsa sheet along . Pack up the trailing egde 1/16 to start with and fly it . If not enough and down trim is still required add another piece. Once happy with the set up make the packing permanent and fill along the wing seating area so wing seat is suported.

The Junior 60 was designed as a free flight model with a slow glider hence the high angle of attack / incidence of the wings. It apppears few plans have been altered to allow  for rc flying over the years as when the occasionally turn up at our field the same issue is present.

Enjoy the J 60 

For reasons already discussed in this thread reducing the wing incidence isn't a good idea, for one  thing it reduces any built in downthrust & it doesn't reduce the angle of attack.